21GF - 2/1 Game Force
Features:
2/1 game forcing conditions:
partner opens 1♦, 1♥ or 1♠ in 1st or 2nd seat;
the next player passes;
the auctions are: 1♦-2♣ (optional semi forcing), 1♥-2♣, 1♥-2♦, 1♠-2♣ (at least 3-4-3-3), 1♠-2♦, 1♠-2♥ (5+);
responder has 13+ HCP;
responder’s suit is a 5+ cards long. Sometimes responder’s suit can contain 4 cards or even 3 cards (1♠-2♣),
the forcing notrump convention:
partner opens 1♥ or 1♠ in 1st or 2nd seat;
no interference;
no 4 spades after 1H opening;
5-12 HCP (responder can have 3-support with 5-6 HCP or 10-12 HCP).
After 1♣ opening, responder commonly skips long diamonds suit if he has a 4-M. So 1♣ - 1♦ = no 4-card major.
Opener’s second bid after game forcing bid:
a minimum: make a low-level rebid in your suit or notrump (1♥-2♣-2♥/2NT);
extra values: make a jump (1♥-2♣-3♥/3NT), a reverse bid (1♥-2♣-2♠) or any bid at the 3-level (1♥-2♦-3♣, 3♦);
18+ HCP balanced: rebid 2NT, then show your extra strength later (1♥-2♣-2NT-3NT-4NT);
other new-suit bids at the 2-level (1♠S-2♣-2♦/2♥) are natural, but don't define your strength;
15-17 HCP and 5=M - rebid 3NT.
Opener’s second bid after the forcing notrump 1♥ - 1NT:
2♣/2♦ - 3+, 11 -18 HCP;
2♥ - 6+, 12 -16 HCP;
2♠ - 4+, 17+ HCP;
2NT - 16-18 HCP;
3♣/3♦ - 4+, 19+ HCP;
3♥ - 6+, 16+ HCP;
3♠ -
3NT - 19+ HCP;
4♥ - 7+, 16+ HCP (8+, 13+ HCP).
Opener’s second bid after the forcing notrump 1♠ - 1NT:
2♣/2♦ - 3+, 11 -18 HCP;
2♥ - 4+, 11 -18 HCP;
2♠ - 6+, 12 -16 HCP;
2NT - 16-18 HCP;
3♣/3♦ - 4+, 19+ HCP;
3♥ - 4+, 19+ HCP;
3♠ (opening suit) - 6+, 16+ HCP;
3NT - 19+ HCP;
4♠ - 7+, 16+ HCP (8+, 13+ HCP).