Fit-jumps by David Bird

A: 3♦. You could bid 2♥ to show a sound raise of spades to some level. It is more accurate to make a fit-jump of 3♦, showing length in both spades and diamonds. This will allow your partner to assess the fit.

Your result so far:

A: 2♠. With only three-card trump support, it is best to cue-bid 2♠, the opponents' suit.

As you can see, you can make fit-jumps opposite an opening bid and opposite an overcall. In the present case, 3♣ would be a fit-jump only when your RHO has doubled or bid. 1♥:3♣ (without any intervention) can be an old-time strong jump shift, or a weak jump shift, or perhaps a Bergen response, showing a heart raise.

Your result so far:

A: 4♦. It is perfectly reasonable to play fit-jumps at the four-level. You must agree this with your partner. Some would treat it as a splinter-bid (showing diamond shortness).

4♦ would also be a fit-jump over a take-out double.

Your result so far:

A: 4♣. Again, your most descriptive bid is a fit-jump. East's negative double suggests spades rather than clubs.

Your result so far:

A: 4♠. With such a big trump fit, you should jump as high as possible straight away.

It will not help partner that much to know that you have a club side-suit. Bidding 4♣ would allow West more space to show his hand.

Your result so far: