ほんすじ
ほんすじ 【本筋 】the main subject [(話題 ) topic, (目的 ) purpose ].▸ 本筋から外れる stray [⦅書 ⦆ digress ] from the main subject [topic , (要点 ) point ] 〘of his talk 〙.▸ 本筋を見失う lose track of the main purpose .▸ まず上司に相談するのが本筋 ⦅あるべき順序 ⦆だと思う I think it's proper to consult your boss first .