noun
double sente; move that is sente for either player
In go, a move that gives the initiative (sente) to whichever player plays it; both sides gain an advantage by taking it. Compare 両後手 (double gote).
この隅の手は両先手だから、どちらが打っても得をする。
This corner move is double sente, so whichever side plays it gains an advantage.
両先手の場所は早めに打たないと相手に取られる。
You should play a double-sente point early, or your opponent will take it.
先手 generally means having the initiative or a move that keeps sente; 両先手 is a specific case where the move is sente for both sides.
Compound of 両 (both) and 先手 (sente, initiative in go). The term is specific to go terminology.