noun
Refers to one's social or moral obligation, or the honor and standing one must uphold. Often used in contexts of fulfilling one's role or maintaining face.
彼は自分の一分を果たすために全力を尽くした。
He did his utmost to fulfill his duty.
武士にとって一分を守ることは何より
For samurai, preserving their honor was more important than anything else.