🏠 Gridcannon

This game was designed by Tom Francis who put the rules online and it's on Boardgamegeek.

There's also a YouTube description of the game courtesy Riffle Shuffle & Roll.

Number cards, 2 to 10, go in the central 3 x 3 grid, while royals go in the perimeter cells around it. Aces and jokers are ploy cards which allow you to change grid cards, but each ploy card played reduces your final score from the maximum six.

At the start of the game, nine number cards randomly form the initial grid while any royals and ploy cards drawn are set aside.

First the royals drawn during the setup need to be placed on the perimeter using this precedence:

1. Next to the highest valued card of the same suit.
2. Next to the higest valued card of the same colour.
3. Next to the higest valued card.

On corners you have a choice of where to place the royal. After the royals have been placed, you may replace any one grid card by moving it to the deck and getting a random replacement.

The goal is to kill all 12 royals on the perimeter using the cards in the grid. A killed royal is face-down. A royal is killed when a card placed triggers the two cards between it and the royal, which means a corner card sometimes kills two royals simultaniously. The value of the two cards needs to be equal or more than the royal card's armour which starts at 11 for jacks, 12 for queens, and 13 for kings. This may increase because cards which cannot be legally placed are added to the royal card's armour.

Besides increasing in armour value, royals are more difficult to kill because the requirements for the two cards between them and the trigger card get harder:

1. For kings, both cards have to have the same suit as the king.
2. For queens, both cards have to have the same colour as the queen.
3. For jacks, any two cards that add up to 11 or more will do.

Each turn, you either take the top card from the deck and place it on the grid if possible, or play a ploy. Cards can only be placed on cards of equal or lower value. If none is available, it gets added to a royal using the same precedence as placing royals, but to the lowest instead of highest valued royal.

If an ace is available, you can discard it to the ploy deck and then clear any of the nine cells whose cards are placed under the deck, replaced by whatever is the top card with royals and ploys again set aside.

A joker allows you to move the top card in a cell to another cell. If there's only one card in a cell, it is replaced by the top deck card.

If you exhaust the deck before killing all 12 royals, you lose.