The game of '01 is the classic game of Darts, played world-wide. The "01"
refers to the fact that the game is played from a certain number of points,
always ending in "01". For example, the common tournament game of 501
(pronounced "Five-Oh-One"), is played from 501 points. Other variations are
301, 601, 801, 1001. The higher point games are usually played by teams.

The object of the game is simple... each player starts with the same score
(501, for example) and the first to reduce his score to zero wins.

Players take turns throwing three darts each and subtract all points scored
from their own beginning score (501). Each player removes his darts and
marks his score before the opponent throws. Darts that bounce off or miss
the board do not score and cannot be rethrown that turn.

The difficult part of the game lies in the finish, known as "going-out". To
win, you must reach zero before your opponent, but you must also reach
exactly zero, and the dart that brings the score down to zero must be a
double. Doubles consist of the numbers in the outside narrow scoring band
and the center (small) bullseye which counts as 50 points and is an actual
double of the outer 25-point bull.

For instance, if you have 2 points left, you must hit a double-1 to bring
the score down to zero. From 18 points, a double-9 would work. If you have
an odd number left (a number that cannot be divided by 2), then darts must
be thrown to reduce the score to an even number, before throwing at a
double. For instance, there is no possible double out from 19, so a way to
finish would be to throw a single-3 first, reducing the score to 16. The 16
can then be "taken-out" by throwing a double-8.

The games of 501, 601, 801, 1001, etc. are all played the same way, except
for starting with more points. The game of 301 is different, however.
Because of the potential for a very short game, 301 has an added
difficulty...the game must start with a double. That is, each player must
hit a double (any double) to start scoring. Each players scoring begins with
the score of the first dart that hits a double.