一寸先(いっすんさき)は闇(やみ)

いっすんさきはやみ
expression
the future is unpredictable; you never know what lies ahead
proverb
1. the future is unpredictable; you never know what lies ahead; one inch ahead is darkness
A proverb meaning that even the very near future is impossible to foresee. Literally 'one sun (about 3 cm) ahead is darkness.' Used to express that anything can happen and one should be prepared for the unexpected.
一寸先(いっすんさき)は闇(やみ)だ。
The future is unpredictable.
人生(じんせい)は一寸先(いっすんさき)は闇(やみ)だから、油断(ゆだん)できない。
Life is unpredictable, so you can't let your guard down.
The business that seemed to be going well suddenly went bankrupt. You truly never know what lies ahead.

A well-known Japanese proverb (諺(ことわざ)). 一寸(いっすん) is an old unit of measurement (about 3 cm), so the literal meaning is 'even 3 cm ahead is total darkness.' Often used in politics — a classic quote in Japanese political commentary. Frequently invoked after unexpected events such as natural disasters, sudden illness, or business failures.