Moriya Hamono cut work-in-progress by producing one packing box at a time

Moriya Hamono, a precision steel-parts maker in Yasugi, Shimane, supplied power-steering parts, motor shafts and punches for the mint, yet its factory held more than three months' worth of work-in-progress. In 2005 it joined a factory-diagnosis tour run by a regional bank, where consultant Hidetoshi Yamada, known for rebuilding Canon and Sony plants, started his walk from the shipping dock—backwards through the line.

Yamada found parts piled on pallets in batches of about 900 pieces per process while the final packing step worked from a separate, overflowing store. His instruction: think in packing-box units, not lots. Make one box, inspect it, hand it straight to the next station—one box at a time instead of a day's or a lot's worth—and let the downstream process limit what flows.

The switch exposed that heat treatment loaded three lots per furnace while later processes could only consume one box, so output had to be paced to what the next process could actually take. That single change turned a 30–40 minute box through inspection and packing instead of letting work sit, shrinking the WIP mountain that had accumulated for years.