The surcoinche in coinche
The surcoinche is the bidding team's comeback when it gets coinched: it multiplies the points by 4.
Coinche, then surcoinche
When the defence coinches (betting you'll fail), the points at stake are already doubled. If you're confident, you can fire back with a surcoinche: you confirm you'll make your contract, and the points are then multiplied by 4 instead of 2.
Who can surcoinche
Only the team that took the contract can surcoinche, and only after being coinched. It's a bid of confidence: you surcoinche when you're nearly sure to make the contract. There's nothing beyond it: after the surcoinche, play begins.
The stakes
The surcoinche changes the whole scale of the deal. Contract made: the bonus is quadrupled, huge. Contract failed: the defence pockets the quadruple instead. At a high level, surcoinching is rare and sends a clear signal, so handle it with real composure. A reckless surcoinche can flip a match in a single deal, either way: only call it when your hand and your partner's bid make the outcome nearly certain.
See also
FAQ
What is a surcoinche?
It's the bidding team's reply to an opponent's coinche. It confirms they will make their contract and multiplies the points at stake by four instead of two.
Who can surcoinche and when?
Only the team that took the contract can surcoinche, and only after being coinched by the defence, before the first card is played.