Negative Doubles
	Negative doubles are typically used to show the unbid major after partner has opened the bidding.
	1C     (1S)     X = negative double, showing exactly 4 hearts and forcing to game, or at least 4 hearts and not strong enough for a 2H bid.
	1C     (1D)     X = negative double, showing at least 4-3 in the majors, 6 + HCP.
	1C     (2D)     X = negative double, showing at least 4-3 in the majors and 8+ HCP or a weak hand with spades (then bidding 2S on the next round)
	1H     (2D)     X = negative double, showing exactly 4 spades and forcing to game, or at least 4 spades and not strong enough for a 2S bid.
	Example 1:
	A 7 2	J 3
	Q 8 3 2	A J 10 9
	Q 7	10 8 5 2
	A 9 5 2	Q J 3
	1C                                  (1S overcall)	X = negative double
	2H	pass
	Example 2:
	A 7 2	K 4 3
	K 8 3	A J 10 9
	Q J 7 3 2	A 8
	A 9	Q J 3 2
	1D                                  (1S overcall)	X= negative double
	1NT	3NT
	pass
	Example 3:
	A 7	K Q 10 9 4 2
	K Q 3 2	10 4
	Q 7 3	J 10 8
	K 9 7 3	Q 2
	1C                                  (2D overcall)	X = negative double
	2H	3S
	pass