one move; a single move
Used in board games like go or shogi for a single move. Also extended metaphorically to a decisive action or strategy.
I carefully considered my next move.
He took on the whole project single-handedly.
only way; only means; sole option
Indicates that there is no alternative; the one remaining course of action. Often used in desperate or final situations.
This is the only way to win.
doing alone; single-handedly; monopoly
Used in the adverbial phrase 一手に to mean handling something all by oneself or monopolizing a task, responsibility, or market. Not used as a standalone noun for 'monopoly'.
See also: 一手に
He took over the negotiations single-handedly.
That company has a monopoly on the market.
He made the decisive move that settled the game.
There's only one way to get through this situation.
The company has complete control over the market.
独り占め means keeping something all to oneself, often with a selfish nuance, while 一手 (in the phrase 一手に) simply emphasizes handling or controlling something entirely by oneself without that selfish overtone.
手段 is a neutral, general word for a method or means, whereas 一手 implies the single remaining option in a difficult or desperate situation.
一手 is the general term for one move in a board game, while 一着 refers specifically to a single move in the game of go.
Compound of 一 (one) and 手 (hand, move). Originally a board game term for a single move, later extended to mean a single decisive action or sole control.