If a ship would lose Japanese nationality due to the transfer of the share of a part owner of the ship or due to a part owner's loss of Japanese nationality, another part owner may demand that the part owner in question sell their share to the other part owner at a reasonable price or put the share up for auction.
船舶共有者の持分の移転又は国籍の喪失により船舶が日本の国籍を喪失することとなるときは、他の船舶共有者は、相当の対価でその持分を売り渡すことを請求し、又は競売に付することができる。
ship
「船舶」
In the part on maritime commerce (except Article 747), a ship used for navigation for the purpose of commercial transactions (商行為), other than rowboats and other boats driven only or mainly by oars.
Defined inArticle 684, paragraph (1)