Ståhlberg Chess
in honour of Gideon Ståhlberg

In Stahlberg Chess the rules are the
same as in orthodox chess, except that one or two extra pieces per player are
placed in the reserve. Before starting, the players must decide whether they
want to use the extra pieces. To make a decision, press on the little black
square. Only if both players choose not to use the extra pieces, then it
becomes a regular game of chess. If white turns down the extra pieces, then
black can overrule this.
If players have elected to include external
pieces, they may either move a piece or pawn, or drop an extra piece from the
reserve. Pieces may only be dropped on a friendly pawn on the second rank. The
removed friendly pawn must immediately be relocated two squares ahead of the
dropped piece. This position, and the position in between, must be empty. If
not, the piece cannot be dropped on the friendly pawn. Should a player refrain
from inserting his extra pieces at these occasions, then he has forfeited his
chance of introducing them. Note that pieces and pawns are allowed to move
before an extra piece has been dropped. You are allowed to make a
pawn-relocation if in check, if the pawn-relocation covers the check. The
relocated pawn can be captured by 'en passant'.
Stahlberg Chess is
normally only played with one extra piece each, namely the
Swedish Cannon: after having jumped
any piece, the Swedish cannon can slide and capture like a rook. However, if no
jump move exists it's allowable to slide like a rook, but without capturing. The
Swedish Cannon has about the same value as a bishop. The closest relative of the
Swedish Cannon is the Korean Cannon. A second piece can optionally be used. This
is the Chancellor (Princess): combines the powers of a Rook and a
Knight. It is comparable in strength to the queen. The Swedish Cannon derives
from Swedish Cannon Chess. The Archbishop was
known already in the 17th century.
In
Stahlberg Chess standard chess is included as an option, thereby maintaining the
historical connection. In a tournament, by way of the initial voting procedure,
players can decide to play a traditional game. Introducing the external pieces
implies a weakening of the pawn chain, so it's a difficult strategical question
whether one should wait, or immediately make use of the drop move to advance a
centre pawn two steps. But dropping an extra piece on the king- or queen pawn
could block the development of the bishop. Waiting has its obvious advantages,
although the alternative positions where the piece can be dropped will become
fewer and fewer.
The Swedish Cannon can take active part early in the
game, so one ought to introduce it early. The Cannon can be exchanged for a
light piece that has acquired a good position, or it can threaten an enemy rook
on an half-open file. The Swedish Cannon is stronger than both its counterparts,
the Korean Cannon and Chinese Cannon, making it easier to introduce it in a
context of Western pieces. Its movement is similar to the Korean Cannon, but
the Korean Cannon is stranded when no jump moves are available. This cannot
befall the Swedish Cannon while it is then, and only then, allowed to slide like
a rook, but without capture. Interestingly, if the enemy Cannon has no jumps,
then one can sometimes position a piece so as to provide a jumping option, thus
preventing the Cannon from using his right to move like a rook. Stahlberg Chess
was invented and implemented by undersigned, May 2007.
Gideon Ståhlberg
Stahlberg Chess was created in remembrance of
Swedish grandmaster
You
can download my free Ståhlberg Chess program
here (updated
2009-10-21), but you must own the software
Zillions of Games to be able to
run it (I recommend the download version). Don't miss my other
chess variants. |
© M. Winther (May 2007).