MAXIMAL DOUBLE. A type of competitive double used to invite game when the auction is too crowded for any otherapproach. The following situation is typical:
West North East South
1♠
2♥ 2♠ 3♥ ?
South may have a hand with which he wishes to sign off in 3♠ or a hand worth a game invitation. Either hand can be described if the maximal double is used as a conventional bid inviting game and the 3♠ bid is reserved for use as competitive, not invitational.
If the enemy competition is not in the maximum suit (the one just below South’s), however, maximal doubles are not needed if the partnership has agreed that opener’s bid in the available side suit constitutes a general game try:
West North East South
1♠
2♦ 2♠ 3♦ ?
In this sequence, South can bid 3♥ (conventional, forcing) to invite game in spades and bid 3♠ to sign off, so some advocates of maximal doubles prefer to use this double for penalty. In the sequence
1♥ 1♠ 2♥ 2♠
3♥ Dbl
the double is maximal and 3♠ is a signoff because there is no room to make a bid short of 3♠. Partnerships may agree to use maximal doubles only when both sides have found a fit or whenever the doubler’s side has found a fit. Doubles by responder in Support Double sequences require discussion.
SOURCE: "Conventions", The Official ACBL Encyclopedia of Bridge, 7th ed. Horn Lake: American Contract Bridge League, Inc., 2011, page 297. Print