Gosplan did not set prices or hand out goods directly. Its instrument was the material balance: for each item on the books, sources — output, opening stock, imports — were made equal to uses: production needs, consumption, exports, closing stock. If a balance did not close, the target was amended and sent back down; the cycle repeated between Gosplan, the branch ministries and Gossnab until all of them closed.

The scale of that work is worth stating precisely. In 1973 Gosplan drew up balances for 1,943 of the most important items — enough to cover the supply of roughly 70 % of industrial output. Everything else was unfolded below: the ministries and Gossnab broke the aggregated limits down into specific products. The nomenclature of the actual economy, meanwhile, ran into millions of items.

That is where the failure comes from. It is not that the sums were done badly: between an aggregated line in a balance and a specific product on a shelf there was always a gap, and it was closed by hand — by supply agents’ arrangements, by fixers, by informal swaps between enterprises. The error surfaced not in the calculation but on the ground, months later.