一いっ寸すん先さき

noun

an inch ahead; the immediate future

Literally 'one sun ahead', used idiomatically to refer to what is just ahead or the very near future, often in expressions like 一寸先は闇 (you can't see an inch ahead; the future is uncertain).

• 一いっ寸すん先さきは闇やみだから、明日あしたのことは誰だれにもわからない。