I went here on a class trip w/ my college while studying abroad. Our teacher said the museum was bilingual and that plaques would be in Japanese and English. That was pretty much a lie. Although there was an English guide, other than very brief, uninformative sentences everything was in Japanese.
On the plus side, the Otsuka Ruins across the street are interesting to look at and walk through (beware of mosquitos).
BUT the best part was the 15 minute show on the history of Yokohama...narrated by a giant talking animatronic rooster! The production value of that show was far beyond what I expected...not quite Disney level but pretty higher and better than any other museum I've seen.
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