Playing Easy Harp well
In brief
The 36 hidden cards determine the outcome: prioritize moves that uncover them. Since you can only move one card at a time, avoid building long sequences on hidden cards, and keep an empty column for a king. You can go through the stock as many times as you like.
1. Uncover the face-down cards
A face-down card can't be played and can block an entire suit. Between two possible moves, prefer the one that flips a card, and think about the columns on the right: column 9 hides 8 cards at the start.
In deal EH1-N-AAAAAAF, the winning game starts by moving A♥ from column 5 to its foundation: this earns 10 points and turns over one of the column’s 4 hidden cards (another 5 points), bringing the score to 15. There are then 35 hidden cards left.
Stock: 59 cards; waste empty. Foundations, cards placed: 0 spades, 0 hearts, 0 diamonds, 0 clubs, 0 spades, 0 hearts, 0 diamonds, 0 clubs. Column 1: 0 face down, then 9 of hearts; column 2: 1 face down, then 3 of hearts; column 3: 2 face down, then 3 of diamonds; column 4: 3 face down, then 5 of diamonds; column 5: 4 face down, then ace of hearts; column 6: 5 face down, then 4 of spades; column 7: 6 face down, then 4 of clubs; column 8: 7 face down, then 3 of diamonds; column 9: 8 face down, then ace of spades.
2. Think one card at a time
A sequence built on a hidden card will have to be dismantled one card at a time to uncover it: each card needs its own destination. Before extending a sequence in a column that still has hidden cards, consider where its cards will go later. In the game on the Examples page, after 4 actions, 4♠ could move on its own onto 5♦ in column 4, but 3♥ on top of it must first move elsewhere.
3. Make use of duplicate cards
With two decks, every card has a twin: a black 6 can be placed on any of the four red 7s (two 7s of hearts, two 7s of diamonds). When a card is waiting for a spot, look for where its twin is, or the twin of the card that would take it. The 8 foundations, two per suit, also let two sequences of the same suit be built up at the same time.
4. Keep the empty column for a king
An empty column accepts only a king, and it is the only place where a sequence can move as a unit, provided it is headed by a king. Clear a column when a king is waiting, preferably a king sitting on hidden cards: at action 329 in the example game, the sequence R♠ D♦ V♣ 10♦ moves from column 9 to empty column 8, uncovering D♠.
5. Don’t send everything to the foundations too soon
Aces and 2s can go up without risk. Higher up, a card placed on a foundation can no longer receive a card on the tableau: a 5 of hearts moved up too fast is then missing to take a black 4. The app never moves anything up on its own, precisely to leave you that choice. If needed, the top card of a foundation can be taken back to the tableau.
6. Go through the stock as often as needed
The stock contains 59 cards and can be cycled through as many times as you like without losing points. A waste card you cannot play now will come back on the next pass: there is no rush. Each card moved from the waste to the tableau earns 5 points.
7. Use undo
The app remembers the last 100 actions. When two moves look equally good, try one, look at the card it uncovers, and undo it if that card does not help: undoing also removes the points earned by the move.