FreeCell

The terms in italics are defined in solitaire terminology.

History

One of the oldest ancestors of FreeCell is Eight Off. In the June 1968
edition of Scientific American Martin Gardner described in his
"Mathematical Games" column, a game by C. L. Baker that is similar to FreeCell,
except that cards on the tableau are built by suit instead of by alternate
colors. This variant is now called Baker's Game.

Paul Alfille changed Baker's Game by making cards build according to alternate
colors, thus creating FreeCell. He implemented the first computerized version
of it for the PLATO educational computer system in 1978. The game became
popular mainly due to Jim Horne, who learned the game from the PLATO system and
implemented the game as a full graphical version for
Windows. This was eventually bundled along
with several releases of Windows.

Today, there are many other FreeCell implementations for every modern system,
some of them as part of Solitaire suites. However, it is estimated that as of
2003, the Microsoft version remains the most popular, despite the fact that
it is very limited.

Strategies

A sequence of several cards with alternating colors can be moved at once
by moving cards to vacant cells and/or temporarily placing them in empty
columns. If the move involves temporarily placing a card in an empty column
it is called a supermove in FreeCell terminology.

Cards can be safely moved to the foundations without a chance of being
further used, if the value of the foundations of the different color are
greater than the card face value minus 2, and the value of the other
foundation of the same color is greater than the card face value minus 3.

Culture

FreeCell, highly popular in the United States, has developed its own subculture. Much information about the game can be found at FreeCell FAQ which is maintained by Michael Keller.

While there are actually 52factorial, or approximately 8.06x10⁶⁷, possible games, the original Microsoft package includes 32,000, generated by a presumably 15-bit random number seed. These games are known as the "Microsoft 32,000". Later versions of Microsoft FreeCell include more games, of which the original 32,000 are a subset.

The Internet FreeCell Project by Dave Ring, which was finished in October
1995, tried to analyze which of the Microsoft 32,000 were solvable. Ring
assigned 100 consecutive games chunks across volunteering human solvers and
collected the games that they reported to be unsolvable, and assigned them
to other people.

The only game in the Microsoft 32,000 that proved to be unsolvable by anybody
(or any computerized solver) was No. 11,982. Given No. 11,982, Maria Feliany, an expert FreeCell player, could place only two cards into the foundations. There are also two deliberately unsolvable games, numbered -1 and -2, that were included as a kind of easter egg by some prankster at Microsoft.

One way to "win" at any Microsoft Freecell game is to push Ctrl-Shift-F10 at any time during the game. Click Abort to win, Retry to lose, or Ignore to cancel. Double-click any card for the results.

Automatic Solvers

One of the passions of several FreeCell enthusiasts was to construct computer
programs that could automatically solve FreeCell. Don Woods wrote a solver
for FreeCell and several similar games as early as 1997. This solver was
later enhanced by Wilson Callan and Adrian Ettlinger and was incorporated
into their Freecell Pro software.

Another known solver is Patsolve of Tom Holroyd. Patsolve uses atomic moves,
and since version 3.0 incorporated a weighting function based on the
results of a genetic algorithm that made it much faster.

Shlomi Fish started his own solver starting of March 2000. This solver was
simply dubbed Freecell Solver.
This solver is unique because it can use meta-moves, groups of
moves that aim to achieve a certain end. The most comprehensive list of solvers that is known, contains links to other solvers. A note which is in order is that new solvers are constantly written as part of assignments or projects of some university courses.