- 'In general it is not used by players of Acol, but is more commonly employed in 5 card major systems; especially those that use a prepared club, rather than better minor. The opening bid of 1♣ will therefore have shown either clubs or a balanced hand.
Maybe so in the UK but the cornerstone of the Walsh system — as presented to Eastern Scientific and unscientific players by Max Hardy in Five Card Majors Western Style — is the opposite. 1♣ tends to deny four diamonds. Strain to open 1{{Diams} with both minors; there is no minimum suit quality. At once that underwrites responder bypassing diamonds to show a 4-card major and using 1♣ - 1♦ for many balanced hands without diamonds (because opener's diamond raise is a reverse, strong and infrequent).
In Five Card Majors but subsequently dropped by Hardy, opener's third call in clubs following diamond preference confirms a minimum hand with only four diamonds: 1D 1X; 2C 2D; 3C.
Standard American authorities long before Richard Walsh taught opening a higher 4-card suit and rebidding a lower 5-card suit on many minimum hands, and that remains true regarding 5-6 shape. Afaik those opening bids were not worthy of alert or special explanation then, nor was the rebid that might be a longer suit, nor was the Walsh 1♦ opening bid during Walsh's time. As standard bidding disintegrated, however, The American alert system evolved to teach players, or to protect players from, many treatments that were once simply good bridge. --P64 (talk) 12:10, 1 April 2010 (UTC)
responding 1D
editResponding 1♦ tends to deny four hearts or four spades —as opening 1♣ tends to deny four diamonds. Responding 1♦ may be waiting with a balanced hand too weak to respond 1N (constructive) or 2N (forcing) —as opening 1♣ may be waiting, with a balanced hand too weak to open 1N (strong) or 2N (superstrong). The 1♦ response is/was? alertable in the ACBL because the primary suit may be clubs; indeed responder (with or without a diamond suit) may plan to rebid clubs rather than notrump. (The direct single raise is forcing and the weak jump raise requires a very good fit: inverted minor raises.)
The 1♦ response followed by clubs preference obscures the minor lengths, as the 1♦ opener followed by clubs rebid obscures obscures the minor lengths. The crucial difference is that minimum opener should pass 2♣ rather than prefer 2♦. Following 1C 1D; 1M 2C; pass is routine and 2D is strong (14)35 or (04)36, whereas following 1D 1M; 2C 2D is routine.
If opener rebids notrump, the pass of 2C preference remains routine; because opener has not confirmed clubs, the 2C preference tends to show primary clubs. Following 1C 1D; 1N 2C tends to show primary clubs and opener's pass is routine.
Much the same is true at the three-level Following 1C 1D; 1M confirms clubs, so responder's jump preference 3C may hold clubs only, a balanced hand that would have raised 1N to two. Opener's diamond preference 1C 1D; 1M 3C; 3D accepts the invitation to game and shows short spades (maybe 2425).
(Unless the partnership uses special bids with full three-suiters 1C 1D; 1H and 2H are natural bids that confirm clubs but maybe only 4414. The same is true for 2S and for strong hands that rebid 1S if the partnership requires uses suit quality to order the rebids with strong three-suiters. Unless opener rebids clubs eventually, responder may never be sure of a 5-card suit.
(Opener's diamond raises confirm five clubs, as do diamond preferences following a major rebid. The single raise 1C 1D; 2D is a reverse, and it must be reasonable to use the partnership "systems on", whatever the system may be. Strong but nonforcing may be reasonable too.)
(Opener's diamond reply to a takeout double is a reverse, by definition, and it must be reasonable to use the partnership "system on", whatever the system may be. Again strong but nonforcing may be reasonable too, at the two-level.)
weak jump shifts
editThe Walsh system presented by Hardy includes weak single jump shift responses for all pairs of suits, ranging in level from 1C-2D to 1S-3H. Any weak jump shift response tends to deny a side 4-card major (with a major the hand should be too weak for a 1-level response including 1S-1N with four hearts). Jump shift 3m rebids remain weak on the second round if opener rebids on the one-level. Rather than bypass a 4-card major responder tends to show it and use the 3m jump shift rebid if available. There are eight auctions if I count correctly. 1H 1S; 1N 3m (two auctions) is weak but some weaker hands would jump directly to 3m 1D 1M; 1X 3c (three auctions) is weak but some weaker hands would jump directly to 3c 1C 1M; 1X 3d (three auctions) is weak but some weaker hands would jump directly to 2d The delayed raises should be integrated with conventional rebids by responder, where I do not plan to cover the Walsh-Hardy versions of fourth suit and new minor. 1m 1M; 1N 3m (six auctions)
other special auctions
editWhat other auctions may need special agreement in order to specify the consequences of Walsh one-level bidding? Here is a selection with some comments.
1C 1D; 2N