"A Moment") is a song recorded by Japanese singer Shizuka Kudo.

"Isshun" was written by Luna Sea lead vocalist, Ryuichi Kawamura, under the pseudonym ЯK.

The song is composed in the key of G-sharp major and Kudo's vocals span from G3 to C5.

Kudo described her own vocal performance on the track as reminiscent of her old singing style.

[3] It fell ten positions to number 39 the following week, recording sales of 7,000 copies.