Many Rules in One Game
I was inspired by the thought of a game in which, for example, the
rules of Cylindrical Chess might be valid on all the light squares,
while on all the dark squares the rules of Alice Chess would be in
effect; this seemed like a clever new idea which deserved more
discussion because not only could you have different rule sets by
geography, you could also have different ones by time, as in
List Chess -- Multiple Rules at Different Times
- A list of games is chosen by mutual agreement of the two
players. For best results, there should be an odd number of
games on the list, and the number of games should be less than
one fourth of the expected number of turns in the game.
A short and conservative list might be, for example, FIDE Chess,
Nutty Knights versus the same army,
and Clobberers (both sides
use the Colorbound Clobberers).
- White chooses a game from the list; it will be the rules for his
first move. Black chooses a set of rules that has not already
been chosen. White makes a move and chooses one of the remaining
rule sets. Repeat as needed.
- When each of the games has been used once, the players choose
from games that have been chosen only once.
- There are two kinds of checkmate, pictorial and functional.
Pictorial is when you are still in check at the end of your
move, according to the current rules. It is checkmate, even if
the rules change so that your King can't be captured.
Functional checkmate is when you are not in check according to
the current rules, but when the rules change the opponent will
be able to capture your King.
Observations about List Chess
If there is just one game on the list, it is exactly as though you
weren't playing List Chess at all. If there are two games on the
list, the first player has a huge advantage. If there are three
games on the list, the advantage of choosing first is evidently
balanced -- on White's first move (when choosing the rule set for
the second move) only one game is left to be chosen, and despite
what Microsoft would have us believe, if you have only one choice
you have no choice. If there are a thousand and one rule sets on the
list, the first player has a marked advantage because the game will
never last long enough to exhaust the list.
You can see more than one move ahead. However, the tactical
complexity of seeing three ply when there are 64 rule sets to be
chosen from is 249984 (64 times 63 times 62) times as large as the
tactical complexity of FIDE Chess.
This game may be playable with a short and conservative list of
By complete coincidence, I was going through some old stuff and
found List Chess, which was mentioned in my NoST column in 1976 or
1977, and which makes such an excellent example here. It makes me
want to design a game called Coincidence Chess, but I have no idea
what the rules would be; and it shows that multiple rules may be a
clever idea, but not a new one.
The first three rules of List Chess are the specific rules that make
this game fair and playable. The fourth rule is a meta rule, a rule
that defines how to handle the transition from one rule set to the
next, as they change at different times.
If you have multiple rule sets on the same board at the same time,
for example one game's rules apply to light squares and another to
dark, the required metarule is this:
An additional metarule is implied: when the rules change from FIDE
Chess to Shatranj, the piece that started the game on d1 changes
from being a Queen to being a Ferz, and so on. Descartes might know
how best to phrase this metarule, but I can only give an example.
- Movement is determined by the rules of the origin square; this
also determines whether a capture can be attempted on the
- The effect of an attempt to capture is determined by the rules
of the destination square.
Too Many Rules
Now that we have a metarule that covers having different rules in
space and another that covers having different rules in time, it's
possible to specify a game that goes beyond sanity:
You can see that the game is properly and fully defined, it is a
fair game (both players have an equal chance), and that is playable
(not by mere humans of course) as well as interesting (to those who
can play it).
- start with a list of about 300 million rule sets
- Each turn, each player assigns a different rule to each of the
262144 squares of a 64x64x64 3D chessboard, and makes a move
(just like List Chess).
A more humble example of a game with rules that vary both in space
and in time is Piazza San Marco Chess.
Exceptions to the Metarules
Not all games fit into the pattern.
In general, if a game expands the board, its effects in the
multirule context are undefined; for example, if the rules of
Alice Chess apply this turn, perhaps you can move your King onto the
Looking Glass board and there find safety? Is the second level of a
3D chessboard equivalent to the lookingglass board of Alice?
Another example of an interesting situation not covered by the
metarules is Relay Chess. In general, the idea of relay is that a
piece defended by a friendly piece gains the powers of the defender;
but when the rules are different on g1 and e2, the Pawn on e2 that
is defended by the Knight on g1 gains what power?
It is probably best not to include such rulesets in the game.
So far, multiple rules on the same board seems less interesting than
multiple pieces on the same square; however, the interesting results
I got from examining crowded squares came from examining the less
obvious possibilities of rules for crowds.
As an example of an unobvious rule for multiple rules in the same
game, let's try Compass Chess: different rulesets apply in different
directions. For example, if you are moving North, the rules of FIDE
Chess apply, and if you are moving South, the rules of Clobberer
Chess (clobberers versus clobberers) apply.
This game doesn't really work well as an example, or perhaps as a
game. You need to choose 16 (north by northwest, and so on)
different rule sets, and in the end the result is the same as if you
had defined one rule set with specific moves allowed for each of the
pieces. (However, specifying it as the 16 rule sets is probably
It's a bit confusing to think about. If you try to move your
Knight-thing (the piece that started on g1) to the Northeast, you
might be able to make a Fibnif or a Waffle move (depending on what
game is chosen for that direction); if you try to move
North, perhaps you can make a WD move. In other words, the pieces
may gain greatly in value, or in some cases they may lose value.
When choosing the 16 rule sets, you'd have to be careful to make a
fair game -- North is always North, and forwards for W is North but
forwards for Black is South.
Influence Chess is another unobvious use of multiple rule sets on
the same board.
Each piece type (R, N, B, Q) comes from a different game, and
behaves according to the rules of that game. In addition, all
adjacent pieces also have the option of using the rules of that
game. Kings and pawns can't be influenced. However, enemy pieces
(other than K and P) can be influenced.
is better than adjacent. There's a certain strangeness
to using the power of a Queen to relay the ability to make a Knight
move. In that case, the name of the game should perhaps be Legal
Depending on which games you choose the rulesets from, this could be
I have exhausted my own brain, but doubt that I have exhausted the
possibilities of different rules on the same board. Please
feel free to demonstrate that I failed to find the best new idea.
Written by Ralph Betza.
WWW page created: May 7, 2001.