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+# CORPUS-0003
+## Money Has Purchasing Power
+### Status: Training Corpus Seed
+### Layer: Layer_0--Primitive_Facts
+### Purpose: Teach that coins matter because of what they can command in a specific place and moment
+### Repository Path: docs/training/corpus/Layer_0--Primitive_Facts/CORPUS-0003-money-has-purchasing-power.md
+
+---
+
+## 0. Principle
+
+Money is not only coin count.
+
+Money matters because of what it can command.
+
+One as, one sestertius, or one denarius has meaning only when connected to prices, needs, and location.
+
+---
+
+## 1. Roman-Visible Example
+
+A trader has 16 asses.
+
+This may be displayed as 1 denarius.
+
+But the important question is not only:
+
+> How many coins does he have?
+
+The important question is:
+
+> What can those coins buy here today?
+
+In one moment, 16 asses may buy food, lodging, small tools, porter labor, or part of a transport arrangement.
+
+In another moment, after a shortage or delay, the same 16 asses may command less.
+
+---
+
+## 2. Minimal Purchasing Power Structure
+
+Purchasing power depends on at least:
+
+1. coin stock
+2. local prices
+3. urgency
+4. available supply
+5. seller willingness
+6. buyer reputation
+7. timing
+
+Coin stock is counted.  
+Purchasing power is interpreted.
+
+---
+
+## 3. Incorrect Modern Assumption
+
+Incorrect assumption:
+
+> More coins always means more economic power.
+
+Correction:
+
+> More coins usually help, but economic power also depends on local prices, access, trust, and timing.
+
+A trusted trader with fewer coins may obtain goods on credit.  
+A stranger with more coins may be refused, delayed, or overcharged.
+
+---
+
+## 4. Simulation Use
+
+This principle supports:
+
+- coin accounting
+- buying power modifiers
+- local price indexes
+- credit access
+- scarcity effects
+- status-based access
+- liquidity decisions
+
+The model should not treat coin balance alone as full economic power.
+
+---
+
+## 5. Canonical Test
+
+If the model sees:
+
+> The trader has 1 denarius.
+
+It must ask:
+
+- where is he?
+- what does he need to buy?
+- what are local prices?
+- is supply available?
+- will sellers deal with him?
+- can he use credit instead of coin?
+- does spending now reduce later options?
+
+Only then can the coin amount be interpreted.
+
+---
+
+## 6. Success Condition
+
+If the model stops asking only “How much money?” and starts asking “What can this money command here and now?” this file is functioning correctly.