英語候補off one's guardhaving weak defensespoor at preventing one's opponent from getting an underarm gripvulnerable (to attack)
巻き替えまきかえ相撲changing from an overarm to an underarm grip on one's opponent's beltwinding a replacement thread, wire, etc.
腕を返すかいなをかえす相撲to place one's arms under those of the opponent and lift them up, in order to prevent an overhand grip on one's mawashi
右四つみぎよつ相撲hold in which both wrestlers obtain an underarm grip with the right hand and an overarm grip with the left