A game try (also called a game trial bid) in the card game of bridge is a bid that shows interest in bidding a game and asks partner to help in making the decision.
For example, (using Acol or Standard American bidding) if opener, with around 16-17 HCP, bids 1♥ and partner responds 2♥ (showing 6 – 9 support points) opener is in a quandary: if responder has a maximum strength hand, with well-positioned high cards, then game will probably make; but the information revealed so far is not accurate enough for either partner to decide whether to play in game or only part score.
Originally, opener would make a game try by bidding 3♥ (inviting game) and responder would then bid game with maximum (8-9) points or pass with minimum (6-7) points.
Modern game try bids permit more accurate decision-making. Following a simple raise by partner (e.g. 1♥ – 2♥), opener bids a new suit to show extra values. By partnership agreement, this can be a long suit, short suit, or help suit game try. Whichever method has been adopted, responder will evaluate the additional information and make one of the following choices: sign off in three of the agreed suit; jump to game in the agreed suit; jump to game in notrump if the suit is a minor; or make a counter try in yet another new suit.
Prior partnership agreement is needed to determine which variety of game try is being used:
Because 11 tricks are required for a minor suit game, most players prefer to investigate the possible optimum contract of 3NT before settling for a minor suit contract (game or part score) and thus a trial bid new suit shows a stopper in that suit for NT purposes, e.g.: 1♦ – 2♦; 2♠ shows game going strength and a stopper in spades
When using any of the above methods of game tries, it is common that a rebid of 3 of the agreed suit is not a game try, but simply an attempt to block the opponents from entering the bidding at a low level. Responder will then pass. As an example (1♥ – 2♥; 3♥ – pass)