Where does “Ямагути” come from?

Ямагути (Russian) comes from Japanese 山口, from Japanese 口, from Japanese くち, from Japanese 朽ちる.

Ancestry of “Ямагути”, step by step

StepLanguageWordMeaning
1Japanese山口—
2Japanese口mouth; opening; the mouth
3Japaneseくちmouth
4Japanese朽ちる—
Every word from Japanese 朽ちる →Every word from Japanese くち →Every word from Japanese 口 →