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presence (e.g. of an observer); observation; observer; witness
trading session (at an exchange)
rising from a crouch to charge; initial charge; face-off
立ち会いが必要な手続きだ。
This procedure requires a witness.
契約時には必ず立ち会いをお願いしている。
I always ask for someone to be present when signing contracts.
医師の立ち会いのもとで手術の同意書にサインした。
I signed the surgical consent form in the presence of a doctor.