Description

MatriO is a card and board game based on matrix multiplication. The game is played with standard (usually miniature-sized) playing cards and a special board, using specially designed markers to maintain player scores.

The board is laid out with three grids, a 3x4 grid and a 4x3 grid of card-sized trays and a 3x3 grid where players' "dot markers" are placed during the game. One of the card-tray grids is positioned to the left of the 3x3 grid, and the other card-tray grid is positioned above the 3x3 grid. The trays are labeled by card suit, a total of six trays for each suit.

Players are each dealt 13 cards (jokers are left in the deck, and the 4 of clubs and 10 of diamonds are discarded in advance of dealing). Players take turns placing a card in one of the trays on the board. If there are empty trays labeled with a given suit, then cards of that suit may only be played in one of those empty trays, and suited cards may not be played in an empty tray labeled with a different suit. Jokers may be played anywhere at any time.

When a player completes a row-column combination by filling the last empty tray of a row or column, the player places one of their "dot makers" in the cell of the 3x3 grid corresponding to the row and column combination they have just completed. The sum of the products of the correspondingly positioned cards in the row and column become that makers "dot score". This score can change throughout the game as other cards are laid in trays in that row and column.

When all 9 cells in the 3x3 grid are filled by players' dot markers, any player with no dot markers on the board is out of the game and their cards are discarded.

Remaining players continue to place their cards. When those players have plaid all their cards, the winner of the game is the player whose dot scores total is highest.

Numerical scores of cards are as follows: Queen of Spades: 13, all other black face cards 10, all black number cards their own numerical value. All red face cards are -10, and all red number cards are negative their own value. Jokers are 0.

—description from the designer