Balancing refers to making a non-pass call to prevent passing out. For an opening, this means opener is at the 4th seat.
Since there is no more opponent to preempt, aggressive preempts are pointless. As a consequence, except 4♠ and 4♥, there are no more openings from 3NT on.
The weak 2s are still preemptive, which shows < 12 HCP and 6+ cards. However, a balancing weak 2 shows more offensive values than other seats.
- 12+ points
- Both vulnerable
- 11+ points
- None vulnerable
- 10+ points
- 9+ points
Why not play strong 2s for the balancing seat? Weak 2s greatly avoid shitty auctions like 1♥-1NT; 2♥-3♥; pass.
Opening 3 of a suit shows 7+ cards and requires opening offensive values (13+ points) but no opening defensive values (< 12 HCP).
Signoff 4♥ & 4♠
These two are the only openings beyond 3NT because major games are so profitable. They now stand for 4♥ and 4♠ openings with 12+ HCP.