Bridge & other card games/response in a major suit
Is there is any way to show 5 cards in a responders major suit. For example I bid 1D partner bids 1H. I have 3 hearts but I have to bid 1NT as I also have 3 spades. my partner had 5 hearts but we had to play in NT and went down.
A one level response in a major suit need only show 4 cards. This is because it is important to be able to find a 4-4 major suit fit. If responder were required to have 5 cards to respond one of a major any 4-4 fit would be very difficult to find, especially if the opener and responder have minimum hands.
Obviously it is possible for responder to have five cards in the major. This can be discovered in invitational or game forcing auctions but may well remain hidden if opener and responder have minimums. There are only a limited number of bids and being able to find a 4-4 fit is more important.
In certain cases, though, it may be preferable for opener to raise responder's major suit even with only three card support. These would include hands in which opener has a singleton or even a small doubleton in an unbid suit so that declarer will possibly be able to ruff losers in the hand with the three trumps and there will be protection if the defenders are able to run tricks in that suit which they might be able to do in a notrump contract. If the auction goes 1D-P-1S-P- you could raise to 2S on S: Kxx H: xx D: AQxx C; KJxx. (Some people might open 1C with this hand but the principle is the same.)
This three card raise of responder's suit should only be done at the two level. If you have a hand that is strong enough to jump to the three level then you should definitely have four card support for partner or else find another bid.