関門かんもん
kammon

Noun

1. barrier; checkpoint; gateway

これ以上いじょうここでもたついてると、後うしろのだい関門かんもんからも増援ぞうえん、挟撃きょうげきされるかもれねーんだぜ。
koreijōkokode motatsuiteruto ushirono dainikammonkaramo zōenga kite kyōgeki sarerukamo shirenē ndaze.
If we hang around here any longer, there could be reinforcements coming from the second gate to take us in a pincer movement!
Noun

2. hurdle; obstacle; trial