{
  "source": "derived from the chain records' chokepoint fields",
  "count": 58,
  "rows": [
    {
      "chain": "aerospace",
      "href": "aerospace-chain/aerospace-chain.html",
      "product": "Aircraft",
      "stage": "Turbine blades",
      "mechanism": "capability",
      "physics": "Single-crystal blades are HOT but BATCH — concentrated by qualification + know-how, not power",
      "holder": "mixed",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "aluminium",
      "href": "aluminium-chain/aluminium-chain.html",
      "product": "Aluminium metal",
      "stage": "Smelting",
      "mechanism": "thermodynamic",
      "physics": "Hall–Héroult runs non-stop; a potline freezes solid if power drops — one big unit at cheap power",
      "holder": "China",
      "share": "~59%",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "International Aluminium Institute (IAI): China's share of world primary aluminium smelting, ~59%. Limit: IAI aggregates member and estimated output — it is not a customs or USGS figure, and smelter output is a different position from bauxite mining or alumina refining."
      }
    },
    {
      "chain": "ammonia",
      "href": "ammonia-chain/ammonia-chain.html",
      "product": "Nitrogen fertilizer",
      "stage": "Haber–Bosch",
      "mechanism": "thermodynamic",
      "physics": "Continuous high-temp, high-pressure synthesis; gas is feedstock + energy → sites at cheap gas",
      "holder": "cheap-gas regions",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "antimony",
      "href": "antimony-chain/antimony-chain.html",
      "product": "Flame retardant · munitions",
      "stage": "Refining",
      "mechanism": "capability",
      "physics": "Trioxide + metal refining — China built the capacity; the mine diversified but refining didn't",
      "holder": "China refine",
      "share": "refine",
      "control": "Sep 2024",
      "conf": "estimate",
      "basis": {
        "kind": "assessment",
        "text": "Anchored on public sources. USGS MCS 2026 shows the MINE is diversifying — China ~36% (40,000 of 110,000 t, 2025e), with Russia and Tajikistan now large — so the mine is not the chokepoint. The binding stage is refining: Reuters (Aug 2024) states China 'is the biggest supplier of refined antimony' while it imports its ore, and Project Blue notes feedstock — not refining capacity — is the constraint; USGS confirms the direction via US imports (antimony oxide 66% China). Limit: no source publishes a single world refined-antimony share, so the page asserts refining dominance qualitatively ('refine'), not a percentage — industry places China at ~75-90% of processing, though IEA GCMO 2026 is itself inconsistent (its export-control table gives 44%, its minor-minerals chart p.199 reads ~68-70%) — the spread shows why this is not a settled number."
      }
    },
    {
      "chain": "arsenic",
      "href": "arsenic-chain/arsenic-chain.html",
      "product": "GaAs chips · alloys",
      "stage": "Recovery (by-product)",
      "mechanism": "byproduct",
      "physics": "A by-product of copper/gold smelting — recovered from toxic flue dust, not mined; supply bounded by the host and by nobody wanting to make it",
      "holder": "Peru · China",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "baryte",
      "href": "baryte-chain/baryte-chain.html",
      "product": "Oil & gas drilling mud",
      "stage": "Mine",
      "mechanism": "diffuse",
      "physics": "A cheap, heavy, abundant weighting mineral mined near demand (India/China/Morocco) — no chokepoint, but you can't drill without it",
      "holder": "India · China · Morocco",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "battery",
      "href": "battery-chain/battery-chain.html",
      "product": "Battery cells",
      "stage": "Cell + cathode",
      "mechanism": "capability",
      "physics": "Electrode coating + cell assembly at scale — capital + process capability, ~80% China",
      "holder": "China",
      "share": "~80%",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "IEA Global Critical Minerals Outlook 2026: China produced ~80% of global battery cells in 2025 (also 98% of LFP cathode, ~95% of cathode precursors, over 90% of anode material). The atlas uses ~80% for the cell-manufacturing chokepoint. Limit: cell-output share; capacity is expanding fast outside China (US/Korea LFP lines), and this is the manufacturing stage, not the upstream mineral refining."
      }
    },
    {
      "chain": "beryllium",
      "href": "beryllium-chain/beryllium-chain.html",
      "product": "Aerospace · defence",
      "stage": "Extraction (US)",
      "mechanism": "capability",
      "physics": "Hard-won hydrometallurgy + alloying, guarded by toxicity — concentrated in the US, the non-China chokepoint",
      "holder": "United States",
      "share": "~53%",
      "control": "—",
      "conf": "measured",
      "secondary": "geological",
      "research": true
    },
    {
      "chain": "bismuth",
      "href": "bismuth-chain/bismuth-chain.html",
      "product": "Non-toxic lead replacement · pharma",
      "stage": "Recovery (lead/tungsten)",
      "mechanism": "byproduct",
      "physics": "A by-product of lead and tungsten smelting; China ~88% of production and refining — coupled to hosts, and China dominates the refining",
      "holder": "China",
      "share": "~88%",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "boron",
      "href": "boron-chain/boron-chain.html",
      "product": "Fibreglass · fertilizer · magnets",
      "stage": "Reserves",
      "mechanism": "geological",
      "physics": "Turkey's borate basins (tincal, colemanite) are a geological rarity concentrated in one region and can't be relocated; its state producer Eti Maden claims ~73% of world reserves, though USGS publishes no consistent world total",
      "holder": "Turkey",
      "share": "~73% (co. est.)",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "Eti Maden (Turkey's state boron company) figure: Turkey holds the majority of world borate reserves and production, ~73%. USGS MCS 2026 confirms Turkey is the leading producer (and 90% of US boron imports) but states outright that 'World totals cannot be calculated because production and reserves are not reported in a consistent manner by all countries' — so it prints no world denominator. Limit: a ~73% 'of world' figure cannot come from USGS; it rests on the state company's own number, not an independent primary source."
      }
    },
    {
      "chain": "cement",
      "href": "cement-chain/cement-chain.html",
      "product": "Concrete",
      "stage": "Kiln (local)",
      "mechanism": "diffuse",
      "physics": "Limestone + kilns are everywhere and cement is cheap + heavy → made locally; no chokepoint, only CO₂",
      "holder": "local, everywhere",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "chromium",
      "href": "chromium-chain/chromium-chain.html",
      "product": "Stainless steel",
      "stage": "Ferrochrome smelting",
      "mechanism": "thermodynamic",
      "physics": "Ferrochrome is ~40% power by cost — the furnace follows cheap electricity (KZ/CN)",
      "holder": "S.Africa · KZ · CN",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "cobalt",
      "href": "cobalt-chain/cobalt-chain.html",
      "product": "Battery cobalt",
      "stage": "Mine + refine",
      "mechanism": "byproduct",
      "physics": "A by-product of Congolese copper; can't be mined alone, then refined in China",
      "holder": "China refine",
      "share": "~75%",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "China's share of refined, battery-grade cobalt is ~75% (IEA GCMO 2026 p.121, 'more than 75% of the market in 2025'). The DR Congo mines ~70% (IEA: DRC 'two-thirds' of mined output, eased from a ~75% peak as Indonesia surged to ~15% by 2025; note the DRC's 2025 export quota cut its MARKETED supply further). Limit: refining share is agency-compiled, not a quoted USGS table; the mine figure moved with Indonesia's rise and the export quota."
      }
    },
    {
      "chain": "copper",
      "href": "copper-chain/copper-chain.html",
      "product": "Electrification",
      "stage": "Mine lead-time",
      "mechanism": "diffuse",
      "physics": "Mining is diversified and switchable; the limit is TIME — a decade to open a mine",
      "holder": "diversified",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "data-centre",
      "href": "data-centre-chain/data-centre-chain.html",
      "product": "AI compute",
      "stage": "Grid connection",
      "mechanism": "diffuse",
      "physics": "Power + grid connection are local and switchable — the limit is megawatts, not one country",
      "holder": "—",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "defence",
      "href": "defence-chain/defence-chain.html",
      "product": "Weapons systems",
      "stage": "Many inputs",
      "mechanism": "capability",
      "physics": "A composite — inherits its inputs' China-processed capability (magnets, gallium, antimony, tungsten)",
      "holder": "China (many)",
      "share": "—",
      "control": "multiple",
      "conf": "measured"
    },
    {
      "chain": "displays-indium",
      "href": "displays-indium-chain/displays-indium-chain.html",
      "product": "Displays (ITO)",
      "stage": "Refining",
      "mechanism": "byproduct",
      "physics": "Refined electrolytically at MODEST temp — concentrated because it rides on zinc, not by heat",
      "holder": "China",
      "share": "~70%",
      "control": "Feb 2025",
      "conf": "measured"
    },
    {
      "chain": "electrolyser",
      "href": "electrolyser-chain/electrolyser-chain.html",
      "product": "Green hydrogen",
      "stage": "Iridium (PEM)",
      "mechanism": "byproduct",
      "physics": "The scale limit is iridium — a trace by-product of platinum mining (future-tense)",
      "holder": "South Africa",
      "share": "—",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "assessment",
        "text": "Qualitative — no single national share. The scale limit for PEM electrolysers is iridium, a trace by-product of South African platinum mining. Limit: this is a materials-scaling constraint, not a country-concentration percentage."
      }
    },
    {
      "chain": "ev",
      "href": "ev-chain/ev-chain.html",
      "product": "Electric vehicles",
      "stage": "Assembly",
      "mechanism": "diffuse",
      "physics": "Assembly is switchable and localises near demand; the real chokepoint is upstream (battery/magnet)",
      "holder": "China",
      "share": "~70%",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "IEA Global EV Outlook: China assembled ~16M of ~22M electric cars in 2025 (~70%). Limit: this is a production-location share that localises behind tariffs and shifts yearly; assembly is not the real chokepoint (the battery and magnet chains are)."
      }
    },
    {
      "chain": "fibre-optics",
      "href": "fibre-optics-chain/fibre-optics-chain.html",
      "product": "Optical fibre",
      "stage": "Preform",
      "mechanism": "capability",
      "physics": "Vapour-deposition preform-making — a few firms hold the process know-how",
      "holder": "US · JP",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "fluorine",
      "href": "fluorine-chain/fluorine-chain.html",
      "product": "Chips · batteries · cooling",
      "stage": "HF",
      "mechanism": "capability",
      "physics": "Fluorspar → HF → fluorochemicals; the gateway chemical, ~60% China",
      "holder": "China",
      "share": "~60%",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "gallium",
      "href": "gallium-chain/gallium-chain.html",
      "product": "GaN / GaAs chips",
      "stage": "Recovery",
      "mechanism": "byproduct",
      "physics": "Trace by-product of alumina/zinc refining — bounded by the host, not gallium demand",
      "holder": "China",
      "share": "~99%",
      "control": "Jul 2023",
      "conf": "measured"
    },
    {
      "chain": "germanium",
      "href": "germanium-chain/germanium-chain.html",
      "product": "IR optics · fibre",
      "stage": "Recovery",
      "mechanism": "byproduct",
      "physics": "By-product of zinc residues + coal fly ash — can't scale on its own; USGS states producers do not publicly report germanium output, so the share is an estimate",
      "holder": "China",
      "share": "~85% (est.)",
      "control": "Jul 2023",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "China's share of germanium is high but IEA's own 2026 figures span a wide band: its export-control table gives 94% while its strategic-minor-minerals chart (p.199) reads ~78%. USGS confirms China is 'the leading global producer' but publishes no share, calling the data 'difficult to verify.' The atlas uses ~85% as a central estimate. Limit: germanium is a poorly-measured zinc/coal by-product; credible figures range ~60-94% and <10% of contained gallium/germanium in ores is even recovered."
      }
    },
    {
      "chain": "graphite",
      "href": "graphite-chain/graphite-chain.html",
      "product": "Battery anode",
      "stage": "Spherical anode",
      "mechanism": "capability",
      "physics": "Spheronising + purifying + coating flake into anode — ~95% China",
      "holder": "China",
      "share": "~95%",
      "control": "Dec 2023",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "IEA Global Critical Minerals Outlook 2026 (p.172): China's share of battery-grade graphite supply is ~94% in 2025 (falling to 91% by 2035) and of mined natural graphite ~80% (down from 84% in 2023, →53% by 2035 as Africa/Canada/Brazil ramp). The atlas uses ~95% for the anode chokepoint (the spherical/coated anode step, ~94% per IEA; the uncoated spherical precursor specifically approaches 100% per Benchmark) and ~80% for the flake mine. Limit: the exact anode figure depends on the processing step."
      }
    },
    {
      "chain": "grid",
      "href": "grid-chain/grid-chain.html",
      "product": "Electricity grid",
      "stage": "Grain-oriented electrical steel (transformer cores)",
      "mechanism": "capability",
      "physics": "Transformer cores need grain-oriented silicon steel, a patented, capital-heavy mill process. The equipment stage downstream is genuinely diffuse (HHI 0.073, 182 exporters) and constrained by factory lead-time, not concentration - but the steel it is built from is the tightest node in the chain, and tightening",
      "holder": "China · Japan",
      "share": "53% of exports (CHN 28.8 + JPN 24.3, 2022–24 mean)",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "heat-pump",
      "href": "heat-pump-chain/heat-pump-chain.html",
      "product": "Heat pumps",
      "stage": "Install",
      "mechanism": "diffuse",
      "physics": "No scarce input; the limit is factory capacity + installer labour — a labour market",
      "holder": "—",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "helium",
      "href": "helium-chain/helium-chain.html",
      "product": "Cryogenics / MRI",
      "stage": "Separation",
      "mechanism": "byproduct",
      "physics": "By-product of helium-rich natural gas; coupled to a few fields, non-renewable",
      "holder": "US · QA · RU",
      "share": "—",
      "control": "—",
      "conf": "measured",
      "secondary": "geological",
      "research": true
    },
    {
      "chain": "lead",
      "href": "lead-chain/lead-chain.html",
      "product": "Lead-acid batteries",
      "stage": "Recycling loop",
      "mechanism": "diffuse",
      "physics": "~60% of lead is recycled from spent batteries, locally — a closed loop, not a geographic chokepoint",
      "holder": "—",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "lithium",
      "href": "lithium-chain/lithium-chain.html",
      "product": "Battery lithium",
      "stage": "Conversion",
      "mechanism": "capability",
      "physics": "Converting spodumene/brine to battery-grade chemical — the concentrated step, China",
      "holder": "China",
      "share": "most",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "China does most of the world's lithium-chemical conversion (spodumene/brine to battery-grade). IEA Global Critical Minerals Outlook 2026 gives China's lithium refining share as ~75% in 2025, up from 70% in 2024 (p.142) — an increasing concentration, even as mining diversifies (Australia, Chile, and now Africa at 14%, though ~65% of new African mine capacity is China-owned). Limit: this is the conversion/refining stage, not mining; the figure has been rising."
      }
    },
    {
      "chain": "magnesium",
      "href": "magnesium-chain/magnesium-chain.html",
      "product": "Aluminium alloys",
      "stage": "Reduction",
      "mechanism": "thermodynamic",
      "physics": "Coal-fired Pidgeon retorts, energy-sited in one Chinese province",
      "holder": "China",
      "share": "~87%",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "computed",
        "text": "Computed from the atlas's own BGS/USGS production series: China sat around 85-88% of primary magnesium across 2019-2023, so ~87%. Limit: the reliable public series is short; this point figure is our read of that series, pending a single clean primary quote."
      }
    },
    {
      "chain": "magnet",
      "href": "magnet-chain/magnet-chain.html",
      "product": "Permanent magnets",
      "stage": "RE separation",
      "mechanism": "capability",
      "physics": "Solvent-extraction separation of chemically-alike elements — an industrial base, ~91% China",
      "holder": "China",
      "share": "~91%",
      "control": "Apr 2025",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "IEA and Adamas Intelligence: China's share of rare-earth separation and refining — the real magnet chokepoint — is ~91%. Limit: separation share is derived from proprietary industry data; published figures cluster 85-92%."
      }
    },
    {
      "chain": "manganese",
      "href": "manganese-chain/manganese-chain.html",
      "product": "Battery manganese",
      "stage": "Sulphate / EMM",
      "mechanism": "capability",
      "physics": "High-purity manganese sulphate + electrolytic metal — ~95% China",
      "holder": "China",
      "share": "~95%",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "IEA Global Critical Minerals Outlook 2026 shows China at ~95-97% of refined battery-grade manganese (high-purity sulphate + electrolytic metal) in 2025 — virtually all recent supply growth came from China. Mining is diversified (South Africa, Gabon, Australia). Limit: applies only to the refined battery-grade stage; the ~95% is read from IEA's refined-production chart."
      }
    },
    {
      "chain": "medical-isotopes",
      "href": "medical-isotopes-chain/medical-isotopes-chain.html",
      "product": "Medical imaging (Tc-99m)",
      "stage": "Reactor irradiation",
      "mechanism": "fragility",
      "physics": "Mo-99 is made in a handful of ageing research reactors; a 66-hour half-life means no stockpile is possible — an irreplaceable, buffer-less capability",
      "holder": "NL · BE · few reactors",
      "share": "~6 reactors",
      "control": "—",
      "conf": "estimate",
      "secondary": "capability",
      "basis": {
        "kind": "count",
        "text": "OECD-NEA: most of the world's molybdenum-99 (which decays to the imaging isotope Tc-99m) is irradiated in roughly six ageing research reactors. Limit: this is a count of major suppliers, not a market share, and the number shifts as reactors retire or restart."
      }
    },
    {
      "chain": "molybdenum",
      "href": "molybdenum-chain/molybdenum-chain.html",
      "product": "Superalloys · refining catalysts",
      "stage": "Recovery + primary",
      "mechanism": "byproduct",
      "physics": "About half a by-product of copper mining (the rest primary); diversified across Chile/China/US/Peru — coupled, but not a severe chokepoint",
      "holder": "China · Chile",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "neon",
      "href": "neon-chain/neon-chain.html",
      "product": "Chip lithography",
      "stage": "Air separation",
      "mechanism": "byproduct",
      "physics": "By-product of steel-plant air separation — captured, not made",
      "holder": "(was Ukraine)",
      "share": "~half",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "Industry and press reporting: Ukraine supplied roughly half of the world's semiconductor-grade neon before 2022. Limit: neon is not in USGS statistics; the figure is industry-reported and was heavily disrupted by the 2022 war — a moving target, not a stable share.",
        "human_check": true
      }
    },
    {
      "chain": "nickel",
      "href": "nickel-chain/nickel-chain.html",
      "product": "Stainless + battery Ni",
      "stage": "Smelting",
      "mechanism": "policy",
      "physics": "Indonesia's raw-ore export BAN forced (China-financed) domestic smelting — built by a rule",
      "holder": "Indonesia · China",
      "share": "~67%",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "nuclear",
      "href": "nuclear-chain/nuclear-chain.html",
      "product": "Reactor fuel",
      "stage": "Enrichment",
      "mechanism": "capability",
      "physics": "Centrifuge enrichment — a licensed service; Russia the largest",
      "holder": "Russia",
      "share": "largest",
      "control": "—",
      "conf": "estimate",
      "secondary": "policy",
      "research": true,
      "basis": {
        "kind": "reported",
        "text": "Russia holds the single largest share of world uranium enrichment — ~45% of enrichment capacity in 2025 per IEA Global Critical Minerals Outlook 2026 (p.224), with China ~14% and France ~11%, so the top three hold ~70% of both conversion and enrichment capacity. Limit: enrichment is a licensed service measured in separative work units, not a mined commodity; 'largest' is a plurality (~45%), not a majority. (China's ~10.8M of ~49M SWU is domestic-focused, not for export.)"
      }
    },
    {
      "chain": "pgm-catalyst",
      "href": "pgm-catalyst-chain/pgm-catalyst-chain.html",
      "product": "Autocatalysts",
      "stage": "Bushveld",
      "mechanism": "geological",
      "physics": "The platinum-group ore is in South Africa's Bushveld Complex (~83% of world PGM reserves); SA leads platinum (~71% of mine output) but palladium is Russia-led",
      "holder": "South Africa",
      "share": "~83% reserves",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "phosphate-food",
      "href": "phosphate-food-chain/phosphate-food-chain.html",
      "product": "Fertilizer / food",
      "stage": "Reserves",
      "mechanism": "geological",
      "physics": "~68% of world reserves are in Morocco (though only ~13% of current production); no substitute for phosphorus",
      "holder": "Morocco",
      "share": "~68% reserves",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "rare-earths",
      "href": "rare-earths-chain/rare-earths-chain.html",
      "product": "Magnets · phosphors · catalysts · polishing",
      "stage": "Separation",
      "mechanism": "capability",
      "physics": "Separating 15+ chemically-alike elements is a vast solvent-extraction industrial base — ~85% China, gating the whole basket, not just magnets",
      "holder": "China",
      "share": "~85% separation",
      "control": "Apr 2025",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "China's share of rare-earth (magnet) separation is ~85%. IEA Global Critical Minerals Outlook 2026 states '85% of magnet rare earth separation' (p.121), consistent with its refined-production charts (~85% in 2025, down from ~91% in 2023 as MP Materials (US) and Lynas (Malaysia) came online) — the one major chain where concentration is falling. (An IEA export-control table gives 91%, an apparent higher/older figure.) Mining is ~70% China. Limit: separation capacity vs realised production differ slightly; this is the separation stage, not mining."
      }
    },
    {
      "chain": "rhenium",
      "href": "rhenium-chain/rhenium-chain.html",
      "product": "Jet-engine superalloys",
      "stage": "Recovery (moly roasting)",
      "mechanism": "byproduct",
      "physics": "A by-product of a by-product — recovered from molybdenum roasting, itself a copper by-product; one of the rarest metals, and it gates single-crystal turbine blades",
      "holder": "Chile · US · Poland",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "semiconductor-inputs",
      "href": "semiconductor-inputs-chain/semiconductor-inputs-chain.html",
      "product": "Chip fabrication",
      "stage": "Photoresist + process chemicals",
      "mechanism": "capability",
      "physics": "Advanced photoresist is ~90% Japan; process gases, CMP slurries and EUV pellicles are each held by a few qualified suppliers",
      "holder": "Japan (resist)",
      "share": "~90%",
      "control": "2019 JP↔KR",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "SEMI / industry: Japan supplies ~90% of the most advanced photoresists. Limit: this applies to leading-edge resist specifically — other inputs (process gases, CMP slurries, EUV pellicles) have their own, different concentrations."
      }
    },
    {
      "chain": "silicon-chip",
      "href": "silicon-chip/silicon-chain.html",
      "product": "Logic chips",
      "stage": "Fab / EUV",
      "mechanism": "capability",
      "physics": "Batch lithography; barrier is decades of process know-how + a single EUV supplier",
      "holder": "TW · US · JP · NL",
      "share": "—",
      "control": "US↔China",
      "conf": "measured"
    },
    {
      "chain": "silver",
      "href": "silver-chain/silver-chain.html",
      "product": "Solar paste · contacts",
      "stage": "Mine (by-product)",
      "mechanism": "byproduct",
      "physics": "~70% a by-product of lead/zinc/copper/gold — output bounded by the base metals, can't scale to demand",
      "holder": "Mexico · CN · Peru",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "solar",
      "href": "solar-chain/solar-chain.html",
      "product": "Solar modules",
      "stage": "Polysilicon + wafer",
      "mechanism": "thermodynamic",
      "physics": "Polysilicon + wafer pulling are power- and capital-hungry, sited at cheap Chinese power",
      "holder": "China",
      "share": "~95%",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "BNEF / IEA: China's share of polysilicon and wafer manufacturing is ~95% at the wafer step. Limit: wafer is the most concentrated stage; cell and module are somewhat less concentrated, and the figures are capacity-based and industry-compiled."
      }
    },
    {
      "chain": "steel",
      "href": "steel-chain/steel-chain.html",
      "product": "Primary steel",
      "stage": "Blast furnace",
      "mechanism": "thermodynamic",
      "physics": "Continuous coke-fired reduction; gated by coking coal + energy",
      "holder": "China smelt",
      "share": "~52%",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "worldsteel 2025 crude-steel production: China 960,810 of world 1,850,279 thousand tonnes = 51.9% -> ~52% (was ~54% on 2024 data; China's share has been declining). Limit: this is a crude-volume share from the authoritative industry body (not USGS) — the real chokepoint is coking coal and energy, and downstream alloy / specialty steel is far more diversified."
      }
    },
    {
      "chain": "steel-alloys",
      "href": "steel-alloys-chain/steel-alloys-chain.html",
      "product": "Ferroalloys (Nb/V)",
      "stage": "Niobium mine",
      "mechanism": "geological",
      "physics": "Niobium is essentially one Brazilian mine (CBMM) — Brazil is ~93% of world mine production, Canada ~7%",
      "holder": "Brazil",
      "share": "~93% production",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "strontium",
      "href": "strontium-chain/strontium-chain.html",
      "product": "Ferrite magnets · pyrotechnics",
      "stage": "Mine (celestite)",
      "mechanism": "geological",
      "physics": "Iran mines ~56% of world celestite from its own mineral deposits — a geological concentration in the ground, not a diffuse market",
      "holder": "Iran",
      "share": "~56%",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "sulfur",
      "href": "sulfur-chain/sulfur-chain.html",
      "product": "Fertilizer · battery metals",
      "stage": "Recovery",
      "mechanism": "byproduct",
      "physics": "A by-product of oil/gas desulfurization + smelting; bounded by fossil-fuel processing, so decarbonization shrinks it",
      "holder": "oil/gas refiners",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "tantalum",
      "href": "tantalum-chain/tantalum-chain.html",
      "product": "Capacitors",
      "stage": "Mine (3TG)",
      "mechanism": "governance",
      "physics": "~68% from DRC/Rwanda artisanal mining — a conflict-mineral supply, not a unique deposit",
      "holder": "DRC · Rwanda",
      "share": "~68%",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "tellurium",
      "href": "tellurium-chain/tellurium-chain.html",
      "product": "CdTe solar · thermoelectrics",
      "stage": "Recovery (copper slimes)",
      "mechanism": "byproduct",
      "physics": "An extreme by-product — recovered from the anode slimes of copper refining; supply is bounded by copper, and it is among the rarest metals recovered at scale",
      "holder": "China · others",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "tin",
      "href": "tin-chain/tin-chain.html",
      "product": "Solder",
      "stage": "Mine + smelt (3TG)",
      "mechanism": "governance",
      "physics": "Concentrated + conflict-linked (Myanmar Wa, 3TG); the ore feed is the fragile part",
      "holder": "CN · ID · Myanmar",
      "share": "~half",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "USGS end-use + International Tin Association: about half of tin demand is solder, and supply is concentrated in China / Indonesia and conflict-linked (Myanmar's Wa State). Limit: '~half' is a use-share, not a concentration share; the governance chokepoint is the ore feed, which no single percentage captures."
      }
    },
    {
      "chain": "titanium",
      "href": "titanium-chain/titanium-chain.html",
      "product": "Aerospace metal",
      "stage": "Sponge + mill",
      "mechanism": "capability",
      "physics": "Kroll sponge + qualified aerospace mill — batch, certification-gated (VSMPO etc.)",
      "holder": "CN · JP · RU · KZ",
      "share": "—",
      "control": "—",
      "conf": "measured"
    },
    {
      "chain": "tungsten",
      "href": "tungsten-chain/tungsten-chain.html",
      "product": "Carbide tools · defence",
      "stage": "APT + carbide",
      "mechanism": "capability",
      "physics": "Mine + APT + carbide processing; ~79% China (67,000 of 85,000 t, 2025) — stable near 80%+ for decades",
      "holder": "China",
      "share": "~79%",
      "control": "Feb 2025",
      "conf": "measured"
    },
    {
      "chain": "vanadium",
      "href": "vanadium-chain/vanadium-chain.html",
      "product": "Steel + storage",
      "stage": "Recovery",
      "mechanism": "byproduct",
      "physics": "Recovered from vanadium-bearing iron ore + steel slag — rides on China's steel",
      "holder": "China",
      "share": "~75%",
      "control": "—",
      "conf": "measured",
      "secondary": "capability",
      "research": true
    },
    {
      "chain": "wind",
      "href": "wind-chain/wind-chain.html",
      "product": "Wind turbines",
      "stage": "OEM + logistics",
      "mechanism": "diffuse",
      "physics": "A steel-and-concrete machine; the limit is scale/logistics + OEM share, and it localises",
      "holder": "China OEM",
      "share": "~67%",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "reported",
        "text": "GWEC: China-headquartered OEMs supplied about two-thirds of new turbines in 2025 (~67%). Limit: this is a supplier-unit share; most turbines are built and sold near where they operate, so it is corporate concentration, not a materials chokepoint."
      }
    },
    {
      "chain": "zinc",
      "href": "zinc-chain/zinc-chain.html",
      "product": "Galvanizing · by-product host",
      "stage": "Smelting",
      "mechanism": "capability",
      "physics": "The host: gallium, germanium, indium and cadmium are recovered at zinc smelters — refining capacity (China ~half) gates them, not just zinc",
      "holder": "China",
      "share": "~half",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "computed",
        "text": "From USGS smelter-production figures: China does roughly half of world zinc smelting — which matters because gallium, germanium, indium and cadmium are recovered there. Limit: '~half' rounds the USGS smelter series; what actually gates the minor metals is the by-product recovery share, which is not separately published."
      }
    },
    {
      "chain": "zirconium",
      "href": "zirconium-chain/zirconium-chain.html",
      "product": "Nuclear fuel cladding",
      "stage": "Nuclear-grade sponge",
      "mechanism": "capability",
      "physics": "Nuclear-grade (hafnium-free) zirconium sponge + cladding is a qualified capability held by a few; Zr and Hf are chemical twins, hard to separate",
      "holder": "FR · US · RU · CN",
      "share": "few",
      "control": "—",
      "conf": "estimate",
      "basis": {
        "kind": "assessment",
        "text": "Our assessment. Nuclear-grade (hafnium-free) zirconium sponge and cladding is a qualified capability held by a few producers (France, US, Russia, China). Limit: this is a capability count, not a market share — there is no clean public tonnage split."
      }
    }
  ]
}