diff --git a/src/chain/chainProfile.js b/src/chain/chainProfile.js
new file mode 100644
index 0000000..9eadf99
--- /dev/null
+++ b/src/chain/chainProfile.js
@@ -0,0 +1,76 @@
+/**
+ * ChainProfile registry — the 10× foundation stone for multi-chain (Pillar 3).
+ *
+ * A single, data-driven source for everything chain-specific that ISN'T an RPC call: money units
+ * (decimals / atomic divisor), the block-timing model (mean block time — which difficulty must
+ * scale to), the adapter family (which wallet/daemon adapter implements it), and the payment-URI
+ * scheme. The adapters (daemon/wallet clients, address validators) plug in per family and read
+ * their params from here.
+ *
+ * The set is exactly what the Smirk wallet supports — btc, ltc, xmr, wow, grin (see
+ * smirk-monorepo packages/core/src/types.ts AssetType) — all proof-of-work / high-variance, so the
+ * "a random block ends your run" mechanic is fair on every one. Adding a chain = one entry here
+ * plus a family adapter, never a fork.
+ */
+
+const DEFAULT_DECIMALS = 12;
+
+// family: 'monero' (subaddress + transfer_split), 'utxo' (BTC/LTC-style), 'mimblewimble' (Grin).
+const PROFILES = Object.freeze({
+    WOW:  Object.freeze({ id: 'WOW',  symbol: 'WOW',  decimals: 11, meanBlockTimeMs: 120000, family: 'monero',       uriScheme: 'wownero'  }),
+    XMR:  Object.freeze({ id: 'XMR',  symbol: 'XMR',  decimals: 12, meanBlockTimeMs: 120000, family: 'monero',       uriScheme: 'monero'   }),
+    BTC:  Object.freeze({ id: 'BTC',  symbol: 'BTC',  decimals: 8,  meanBlockTimeMs: 600000, family: 'utxo',         uriScheme: 'bitcoin'  }),
+    LTC:  Object.freeze({ id: 'LTC',  symbol: 'LTC',  decimals: 8,  meanBlockTimeMs: 150000, family: 'utxo',         uriScheme: 'litecoin' }),
+    GRIN: Object.freeze({ id: 'GRIN', symbol: 'GRIN', decimals: 9,  meanBlockTimeMs: 60000,  family: 'mimblewimble', uriScheme: 'grin'     })
+});
+
+function normalizeId(cryptoType) {
+    return String(cryptoType || '').trim().toUpperCase();
+}
+
+/**
+ * Resolve a chain profile. Unknown/unset falls back to a WOW-shaped default (11 decimals, ~2 min)
+ * so callers never crash on a mis-set CRYPTO_TYPE. Returns a frozen profile object.
+ */
+function getProfile(cryptoType) {
+    const id = normalizeId(cryptoType);
+    if (PROFILES[id]) return PROFILES[id];
+    return Object.freeze({ id: id || 'WOW', symbol: id || 'WOW', decimals: DEFAULT_DECIMALS, meanBlockTimeMs: 120000, family: 'monero', uriScheme: 'monero' });
+}
+
+function decimalsFor(cryptoType) {
+    return getProfile(cryptoType).decimals;
+}
+
+function meanBlockTimeMsFor(cryptoType) {
+    return getProfile(cryptoType).meanBlockTimeMs;
+}
+
+function familyFor(cryptoType) {
+    return getProfile(cryptoType).family;
+}
+
+function uriSchemeFor(cryptoType) {
+    return getProfile(cryptoType).uriScheme;
+}
+
+/** Atomic divisor as a BigInt (10 ** decimals) — safe for ETH-18-scale amounts (none here, but correct). */
+function atomicDivisor(cryptoType) {
+    return 10n ** BigInt(decimalsFor(cryptoType));
+}
+
+function isSupported(cryptoType) {
+    return !!PROFILES[normalizeId(cryptoType)];
+}
+
+module.exports = {
+    DEFAULT_DECIMALS,
+    PROFILES,
+    getProfile,
+    decimalsFor,
+    meanBlockTimeMsFor,
+    familyFor,
+    uriSchemeFor,
+    atomicDivisor,
+    isSupported
+};
diff --git a/src/game/helpers/gameModeUtils.js b/src/game/helpers/gameModeUtils.js
index 5618d56..4357953 100644
--- a/src/game/helpers/gameModeUtils.js
+++ b/src/game/helpers/gameModeUtils.js
@@ -1,3 +1,5 @@
+const ChainProfile = require('../../chain/chainProfile');
+
 const DEFAULT_DECIMALS = 12;
 
 const parseAtomicEnvValue = (val, fallback) => {
@@ -17,13 +19,9 @@ const parseAtomicEnvValue = (val, fallback) => {
     return Math.trunc(num);
 };
 
-const inferCurrencyDecimals = (symbol) => {
-    if (!symbol) return DEFAULT_DECIMALS;
-    const normalized = symbol.toUpperCase();
-    if (normalized === 'WOW') return 11;
-    if (normalized === 'XMR') return 12;
-    return DEFAULT_DECIMALS;
-};
+// Delegates to the ChainProfile registry — one source for all chains (WOW 11, XMR 12, BTC/LTC 8,
+// GRIN 9; unknown -> 12). Previously WOW/XMR were hardcoded and everything else silently got 12.
+const inferCurrencyDecimals = (symbol) => ChainProfile.decimalsFor(symbol);
 
 const getDecimalDivisor = (decimals = DEFAULT_DECIMALS) => {
     const normalized = Number.isFinite(decimals) ? decimals : DEFAULT_DECIMALS;
diff --git a/test/chainProfile_ultra.test.js b/test/chainProfile_ultra.test.js
new file mode 100644
index 0000000..bfd72cf
--- /dev/null
+++ b/test/chainProfile_ultra.test.js
@@ -0,0 +1,49 @@
+/**
+ * ChainProfile registry (Pillar 3 foundation) — one source for chain params across Smirk's five
+ * PoW chains, and the fix for decimals silently defaulting to 12 for anything but WOW/XMR.
+ */
+const ChainProfile = require('../src/chain/chainProfile');
+const { inferCurrencyDecimals } = require('../src/game/helpers/gameModeUtils');
+
+describe('ChainProfile', () => {
+    test('decimals are correct for every Smirk chain', () => {
+        expect(ChainProfile.decimalsFor('WOW')).toBe(11);
+        expect(ChainProfile.decimalsFor('XMR')).toBe(12);
+        expect(ChainProfile.decimalsFor('BTC')).toBe(8);
+        expect(ChainProfile.decimalsFor('LTC')).toBe(8);
+        expect(ChainProfile.decimalsFor('GRIN')).toBe(9);
+    });
+
+    test('mean block time + adapter family per chain', () => {
+        expect(ChainProfile.meanBlockTimeMsFor('GRIN')).toBe(60000);   // ~1 min, fast floor
+        expect(ChainProfile.meanBlockTimeMsFor('BTC')).toBe(600000);   // ~10 min, slow end
+        expect(ChainProfile.familyFor('WOW')).toBe('monero');
+        expect(ChainProfile.familyFor('BTC')).toBe('utxo');
+        expect(ChainProfile.familyFor('LTC')).toBe('utxo');
+        expect(ChainProfile.familyFor('GRIN')).toBe('mimblewimble');
+    });
+
+    test('atomic divisor is a BigInt of the right scale', () => {
+        expect(ChainProfile.atomicDivisor('WOW')).toBe(100000000000n); // 1e11
+        expect(ChainProfile.atomicDivisor('BTC')).toBe(100000000n);    // 1e8
+        expect(ChainProfile.atomicDivisor('GRIN')).toBe(1000000000n);  // 1e9
+    });
+
+    test('case-insensitive; unknown falls back safely', () => {
+        expect(ChainProfile.getProfile('grin').decimals).toBe(9);
+        expect(ChainProfile.isSupported('DOGE')).toBe(false);
+        const fb = ChainProfile.getProfile('DOGE');
+        expect(fb.decimals).toBe(12);
+        expect(fb.family).toBe('monero');
+    });
+});
+
+describe('inferCurrencyDecimals now delegates to ChainProfile', () => {
+    test('WOW/XMR unchanged; BTC/GRIN fixed (were silently 12)', () => {
+        expect(inferCurrencyDecimals('WOW')).toBe(11);
+        expect(inferCurrencyDecimals('XMR')).toBe(12);
+        expect(inferCurrencyDecimals('BTC')).toBe(8);
+        expect(inferCurrencyDecimals('GRIN')).toBe(9);
+        expect(inferCurrencyDecimals('')).toBe(12);
+    });
+});