明暗 めいあん境界 きょうかい せんでしょう
meian kyō kaisendeshō

Noun
Desu Copula

Expresses probability in a polite manner ("probably…") of 明暗境界線

1. Probably the boundary between light and darkness.; Probably the line between clarity and obscurity.

Polite
Presumptive
Conjecture
Astronomy