Why Japan could not simply build Yamato-class ships for Germany

Could Japan have built four Yamato-class ships for Germany and delivered them around Africa?

Not with its historical yard capacity; supplying designs and guns for German construction would be more plausible, though still infrastructure-intensive.

The counterfactual asks Japan to build four Yamato-class ships for Germany and send them around Africa. Its first obstacle is industrial: Japan did not possess spare yard capacity for such an order. Even an early contract would require a major expansion of infrastructure before the ships could be built. Supplying designs and heavy guns while Germany constructed the hulls is more plausible, though Germany would still need substantial facilities of its own.