Half Moon strategy
In brief
Prefer removals that uncover cards in the piles, save reserve cards to unblock the endgame, count face cards before starting a triplet, and check where both copies of a card are before choosing a pair. These are tips, not rules.
Uncover cards
A pair taken from two piles reveals two new cards; a pair taken from the reserve reveals none. The cards hidden beneath the top cards of the piles are the game's real challenge: the more you uncover early, the more choices you have. In the winning game on the Examples page, the first move (5♠ and 6♦) reveals a V♣, which is immediately removed in a triplet.
Save the reserve
The 8 reserve cards can be played at any time, which is precisely why you can wait: they remain available when the piles offer no more moves. In the same game, the first reserve card is not used until move 16, and after 24 moves, 5 are still left.
Count the face cards
The two decks contain 24 face cards: 8 Jacks, 8 Queens and 8 Kings—exactly 8 triples. An extra King on top of a pile blocks everything beneath it until a Jack and a Queen are playable at the same time. When two triples are possible, take the one that frees up the piles with the most cards.
Watch out for duplicates
There are two copies of each card and eight of each numbered rank. Before removing a 4 with a 7, check whether another 7 is playable: take the one covering the most cards. Conversely, a pair that uses the last card of a rank still needed elsewhere may leave another card with no possible partner.
Undo to experiment
Undo restores the cards and deducts the points from the undone move. It lets you try an order of moves, see what the pile reveals, then go back. The final score for a won game remains 520 no matter what.