Differences between Yamato and Musashi in 1/12000 scale

Not until the first refit, after that they had considerable diferences
even for 1/1200 scale.

I believe ppvr is right. There were some differences, but none that would be visible in such a small scale. Several plastic kit companies (e.g., Tamiya) have marketed Yamato and Musashi kits that look quite a bit different, but the differences actually represent stuff that was changed on board both vessels during refits. (Typically they reproduce the Musashiin "as built" configuration and the Yamato as she looked near the end.)

If you want an interesting reading experience (and the chance to study some spectacular draftsmanship), get hold of a copy of Anatomy of the Ship: The Battleship Yamato, by Janusz Skulski. The artwork in that book is almost unbelievable, and it will tell virtually everything about that ship that anybody knows.

Thanks, I was bidding on a Yamato on ebay and wanted to know if I should bail to the Musashi if the price went to high. As it turned out I got the Yamato and Shinano. This will probably be a father/son build.