Destroyer standardization cannot ignore Japanese shipyards

How many more destroyers could Japan build by consolidating its different types?

There is no fixed number; gains depend on timing, design size, yard limits, and whether some requirements are better met by sloops.

The number of additional ships depends on when standardization occurs and which designs survive. Larger destroyers cannot use every yard without infrastructure upgrades, so simply choosing one high-end type may reduce rather than expand output. Two smaller types could preserve access to more building capacity. Planners should also ask whether every hull ought to be a destroyer or whether simpler sloops would meet some escort needs more efficiently.