Responder’s 2^nd bid of 4^th unbid suit

4th Suit Forcing will occur in non – competitive auctions, after partnership has bid 3 different suits. The bid of the 4th suit in this situation is agreed to be Artificial and Game Forcing.

West	North	East	South
			1!c
pass	1!h	pass	1!s
pass	2!d

2!d bid by responder is 4th suit forcing.  4th Suit Forcing is what is called an Alertable bid.  The 2!d bid is completely artificial (says nothing about the diamond suit). It is only to draw attention of opener and game force.

Key points to note while using this convention: 

• The opponents are not bidding. 4th suit forcing only exists in non – competitive auctions. 
• Both North and South are unpassed hands.
• Neither side of the partnership has game forced in earlier bids.
• Responder has 13+ total points

Let’s take a look at 4th suit forcing in action. See the above auction,  North knows that this round has enough for game, but the strain of that game is not final. Auction can conclude even in No Trump.

Let’s talk about responder’s 2nd potential bids, without using 4th suit forcing: 

• 2!s-Shows a weak hand 6-9 HCP. Will indicate sign off.
• 3!s-Shows 4+ Spades and invitational values 10+ HCP. Non forcing. Opener may pass.
• 3 NT:  This will get us to game, but may miss a game in a Major which is our first priority.

Enter 4th Suit Forcing.  Instead of guessing what might be right with this hand we get to use the 4th suit forcing bid to explore our options without the fear of being passed.

West	North	East	South
			1!c
pass	1!h	pass	1!s
pass	2!d	pass	2!s
pass	4!s

Note : Bid of 4^th Minor is only an Alert. When you actually want to bid !c or !d to show 5+ cards and a weak hand, an exception to this rule is implemented via 3!c/3!d. These bids are non forcing.