Three industries, one supply chain
Fireworks, matches and printing all buy paper, board, chemicals and packaging from broadly the same trade, and all three run to seasonal peaks. That means demand concentrates hard before festivals and the ordering decision is taken months in advance from figures rather than from feel.
Regulated material needs records
Chemical inputs in this trade are regulated, and recording batch, grade and quantity on both purchase and sale is not administration — it is what an inspection or a supplier query is answered from, and it cannot be reconstructed after the fact.
Units buy in running accounts
Hundreds of small units buy frequently against production runs and settle on their own cycle, which is exactly the pattern that grows unnoticed. The ledger building itself from the billing means none of it needs a second entry, and a monthly statement settles each account while the run is fresh.