The governor in New Spain confiscated San Buena Ventura to obstruct independent Japanese oceanic trade. The distinction between preventing expertise and discouraging confidence matters here. A successful crossing had already demonstrated navigational ability; the more plausible aim in this interpretation was to stop such voyages becoming routine. Losing the vessel angered the Japanese and weakened the attraction of Spanish trade. It also failed to remove their ability to build more ships. Adams's continuing shipbuilding work made replacement possible.
Chapter · 1:22:20-1:24:10
Spain's seizure of a Japanese ship and its limits
Confiscating San Buena Ventura is interpreted as an attempt to discourage regular Japanese crossings, despite demonstrated navigation and shipbuilding skills.