at a snail's pace; inch by inch
Idiomatic expression describing very slow, gradual progress. Often used adverbially as 一寸刻みに.
Because of the traffic jam, the cars are moving only inch by inch.
The negotiations progressed at a snail's pace.
一寸 (one sun, about 3 cm) + 刻み (cutting, notching), literally 'cutting into one-sun lengths', figuratively meaning very slow, step-by-step progress.