You hold four private cards. Nine additional cards are dealt face-down into a three-by-three Grid and then revealed to the entire table.
Eight lanes run through the Grid: three rows, three columns, and two diagonals.
Your hand consists of all four of your private cards plus the three cards from exactly one lane. The resulting seven-card hand is valid only when all three conditions are satisfied:
All four suits must appear. No exceptions.
The suit distribution must be exactly 3-2-1-1: one suit appearing three times, one appearing twice, and each of the remaining two appearing once.
No two cards may share the same rank. One matching pair makes the entire hand invalid, regardless of its suits.
Most starting hands cannot satisfy all three conditions. Repairing the hand is the heart of GRIVOT.
Lanes are shared. Any number of players may use the same lane. Position 5, the center card, appears in four of the eight lanes, making it the most influential card on the Grid.