1To begin or set about a task; commencement of work (often used as '〜に着手する').
予算が確保でき次第、工事に着手する予定だ。
As soon as the budget is secured, we plan to begin the construction.
新しい商品開発に着手したばかりだ。
We have just started development on a new product.
契約書に署名してから着手してください。
Please start after signing the contract.
2In legal contexts, commencing the execution of a crime; beginning to carry out a criminal act.
検察は被告が犯行に着手したと主張した。
The prosecution argued that the defendant had begun to carry out the crime.
3In board games like go or shogi, the act of making a move.
次の着手を慎重に考える必要がある。
You need to carefully consider your next move.
彼は着手が早く、序盤で優位に立った。
He moved quickly and gained an advantage in the opening.