13  When is a bid forcing?

I can’t give a complete list, this depends on your conventions, but I can start with bids that are not forcing: all suit raises, all suit repeats, all pre-emptive bids, all NT bids (except NT bids which are clearly something else, e.g. 4NT Blackwood, Unusual NT, negative NT).

Forcing bids are usually a new suit; the commonest are 1-level change of suit (forcing for one round), jump bid in new suit (forcing to game).  Take-out doubles are one-round forcing if no intervening bid. Realise that this includes Unusual NT, which is a limited take-out double in effect.  Opener’s two suits are virtually forcing to give preference.

Opening 2C is normally forcing to game (there’s a tiny exception). Another option I have found useful is that an immediate bid of the opponent’s suit is fording to game or suit agreement. If you use this, make sure partner understands it.

Jump bids are not forcing in a suit already bid by the partnership. E.g. 1H followed by 3H is not forcing, whichever partner bids the 3H. Such a bid is invitational and at partner’s discretion. Partner: don’t go 4H if it’s not there! Opener will need more than minimum. A fifth trump is sufficient, or 15 points.