By Bakufu law, a samurai family with the head under the age of 17 could not adopt a child, so if the young head of the family had critical illness or died unexpectedly, the family faced the possibility of ending its line without an heir.
幕府法制では17歳未満の武家は養子を迎えることができず、17歳未満の当主が、危篤状態もしくは急死したとしても急養子を迎えられず家が断絶してしまう可能性があった。