When 2/1 theory first came out , the concept of “fast arrival” came into vogue. This meant every time you were forced to game from either side and you had a minimum, you leapt to game to show your minimum. Over time , this proved notto be a good idea.Unlimited hands were pre-empted by their own partner ! This forced slam investigation to the 5 level which had dire consequences. Even though you had a minimum , your cards were still useful for slam investigation. Q bids opposite an unlimited hand became courtesy Q bids in case partner needed to know. Over time, “fast arrival” opposite an unlimited hand was replaced by “picture bids”.
What are “Picture Bids” ?
These bids are still “fast arrival” but so specifics to paint a picture of your hand to partner. These bids state that you have what you announced but concentrated in your suit or partners suit and no outside controls. If you had outside controls , you would have bid them as a courtesy. These picture bids are not just limited to 2/1 but show up in other places like Jacoby 2NT.
is a picture bid with most of her values in the spade suit and no outside controls.
minimum limit raise with heart duplication.
Lets review some other “picture bids” .
clubs & spades but no outside controls.
this shows very good diamonds & a 4th spade.
How about the double fit hands ? They are picture bids also.
This shows a minimum with no outside controls & all your values in spades & hearts.
Jumps in partner’s major are never splinters. Why ? This is because playing 5 card majors the odds of duplication is just overwhelming. You must give up something to play jumps in partners suit as a splinter and the odds say it is just not worth it. Opening 3 card minors to the queen or jack is a different matter. Having a splinter defined in partners minor is probably a good idea. “Auto-splinters” work on that principle.
is a stiff diamond and a slam try in hearts. This is the auction that I am aware of that you can splinter in partners suit.