The game is so challenging that since its release a few days ago, the developers have had to alter it to make the “easy” version even simpler, Mr Urbahn said.
“If you get really good at the game, you’ll probably win one in every four times. That’s about the win rate among the best players I have seen.”
Churchill Solitaire is free for iPhone and iPad users, but players can pay to undo a move or get a hint, although players who choose to do the latter will earn the disdain of Mr Rumsfeld.
“There are damn few undos in life,” he told the Wall Street Journal.
The app has the approval of the Churchill estate, who will donate their share of the proceeds to charity. Mr Rumsfeld will also donate any profits to military charities in the USA.

A card game expert’s review of Churchill Solitaire, by Tom Townsend
I downloaded Churchill Solitaire on my iPad. While waiting for the necessary operating system upgrade to kick in, I played a few games of standard Windows solitaire on my PC. This is similar to the version of Patience played by my grandfather: seven columns of cards, stackable in descending order of rank, alternating red and black.
You can move cards between these columns, or draw fresh cards one at a time from the deck. Aces are low. When an ace is free you can start a home stack and build upwards in that suit. Build all four suits, ace, two, three and so on up to the King, and you win the game.
Churchill Solitaire is a double-deck Patience, with 104 cards and a rousing military theme. After a couple of games all but the most patriotic players will probably prefer to play with the military band switched off. There are 10 columns, and eight home stacks (victory piles). This provides more options early in the hand, not all of them good.
A novel feature is the Devil’s Six. These cards can be moved only directly to the victory piles, and should be liberated at the first opportunity. Click for fresh cards from the deck in this game, and it sprays them out nine at a time like a machine-gun, directly onto the columns.
The unpredictability of this is what makes the game extra-hard. If you don’t win on your first attempt, or even your second or twenty-third, don’t get angry, just remember the words of the great man: “Success consists of going from failure to failure without loss of enthusiasm”.

How Churchill Solitaire differs from regular Solitaire
The objective is to create eight piles of cards in the top right Victory Rows. Each stack must go in ascending order, starting with an ace and ending with a king.
The twist involves two rows of cards, instead of one, and a “devil’s row” of six cards on the top left, which players must eliminate.
In order to win, these cards have to be moved over to the Victory Rows, without being moved onto the main playing deck.