Card Under
Card under, also called the unknown, is a call-an-ace house rule for a picker who holds the ace of every fail suit they have cards in, so no ordinary call exists. The picker calls the ace of a suit they are void in and lays one card face down as the under card. That card must be played when the called suit is led, it counts as a card of that suit, and it can never win a trick.
Without it, the picker goes alone
An ordinary call needs a suit where the picker holds a fail card but not the ace. A picker holding, say, the ace and nine of spades and no clubs or hearts has no such suit. Under the plain rules they must play alone. Card under gives them a partner instead. It is off by default at Sheepshead Club, and a call-an-ace private table can switch it on (“Card under”). It does not exist at jack of diamonds, where nobody calls anything.
It only applies when nothing else does: if the picker holds all three fail aces, call a ten comes first. And the picker needs at least one fail card to lay under; with nothing but trump, alone is the only option.
How the under card works
- Chosen at the bury. The picker lays it face down from the cards they keep, separately from the bury.
- Out of the hand. It is face down, so it does not count for following suit. Lay the 8♣ under, and with no other clubs you are void in clubs.
- Part of the called suit. When the called suit is led, the under card must be played. For deciding who wins, it counts as the lowest card of the called suit, so it never takes a trick. Its points go to whoever does.
- Leadable. The picker may lead it like any card of the called suit, which drags the called ace out at a moment the picker chooses.
- Never wasted. If the called suit is never led, it is played on the last trick.
A worked hand
After taking the blind, the picker holds:
Q♠ Q♦ J♣ A♦ K♦ A♠ 10♠ 9♠
Spades are the only fail suit in hand, and the picker holds the A♠. No ordinary call exists. With card under on, they call the ace of hearts, a suit they are void in, bury the A♠ and 10♠ (21 points), and lay the 9♠ under for hearts.
When hearts are led, the picker plays the face-down 9♠, which counts as the lowest heart; the partner must play the A♥, which wins unless somebody trumps. Or the picker can lead the under card themselves, as a heart, to bring the ace out on their own schedule.
Which card to lay under
Usually the cheapest fail card you hold. The under card is spent on the called-suit trick whatever happens, and it can never win, so a low card costs nothing while a ten laid under is ten points handed to whoever takes that trick. Our computer players lay the cheapest kept fail card under.
Why “the unknown”
Because the card is face down, the table does not know what it is when it lands. At Sheepshead Club everyone sees it once the trick is taken; a club can set it so only the player who takes the trick sees it.
Related
Play a hand
See it for yourself: deal a practice hand that forces card under, then press Pick. Or open a call-an-ace table with card under switched on.