Responses to major overcalls

The responses to overcalls of 1 ♠
Your Partner who has just overcalled can have between 8 and 17HCP (with more than that he would have doubled). He usually has a strong 5 card suit ... but sometimes a very powerful suit of only 4 cards.

  To resume:
- raises are non-forcing preempts
- hanges of suit can be forcing or not : according to the situation - jump shifts guarantee a 2-suiter hand and a 4-card fit (jump fit) - cue bids show a strong hand of at least 11HCP. - jump cue bids are splinters and show a 4-card fit.

2) The various responses

• With a weak balanced hand: PASS
With 8 well positioned HCP and 3 trumps: support at the lowest level.
• With more than 8HCP and 4 trumps, push up the preempt by supporting with jump (non-forcing).
• With 11HCP and 4 or 5 trumps, go to game.
• Without a fit but with a strong 6-card suit, change suit.
• As from 11HCP cue-bid opener's suit
• As from 11-12HCP make a jump shift which guarantees a fit after a major overcall.

Change of suit with jump
It shows:

• a 4-card fit
• 5 strong cards in the new suit
• a strength of at least 9-10HCP, enough to think about game!
• Sometimes a double jump is used which is game forcing.

Splinter
The jump cue bid in the opener's suit is a splinter. It guarantees:

• a 4-card fit
• a void or singleton in the opener's suit
• and enough strength to go at least to game