David,
In fact today's Tradweinds reports a rather different story to that mentioned elsewhere. Apparently 100+ shipyard workers at the Yamanishi yard had a lucky escape by sheltering aboard two ships in the final stages of construction there, the 24,000 dwt bulkers SIDER JOY and TORIPAN. The ships were washed ashore and reportedly damaged, though to what extent is unclear. However, the most important and reassuring thing is that all Yamanishi shipyard workers survived and are accounted for. Ships are designed to float - buildings are not, hence it seems that they made a very wise decision.
Brgds
Phil