裏うら階かい段だん

noun

back stairs; rear staircase

Refers to a secondary or hidden staircase, often at the back of a building, used by staff or for service access.

• ホテルの裏うら階かい段だんを使つかって厨ちゅう房ぼうに行いく。

  I go to the kitchen using the hotel's back stairs.