The Chess Variant Pages

Black holes

About the Game

'Black holes' is a Chess variant played on a board with 40 squares. It was created and developed by Juraj Lörinc during July 1999 for submission to the 40-squares chess variant design contest organized by Homepage of Chess Variants.

I was trying to create game differing in relatively small number of rules from normal chess and soon I found the way to do everything by simply adding one piece. All differences in tactics, strategy and the feeling of game are caused only by its powers and its interplay with other pieces.

The inspiration I had for a long time. I simply wanted to have a game featuring some kind of 'transporter' as it is called at taxonomy page. The ability to transport other pieces on far distances is the main property of the new piece (called simply 'hole'), but it has some others too, often it acts as a normal piece.

I got no inspiration from other variants, really, believe me, just after finishing the game design I found taxonomy page and so I could compare my 'transporter' to known types. Well, it is original enough, it seems...

The name of the game

It is simple to find out why I chose this name. After practising a bit you will have the feeling for 'black' and 'white holes' (objects enter former and leave latter during relativistic moves) and relativistic moves don't preserve energy. I wanted the name to include 'Einstein' in the memory of inventor of relativity theory, but then I remembered that Einstein chess is well known and very different from my invention. 'Black holes' sounds well too, doesn't it? I am sci-fi fan, not physicist, so I don't care about physics background...


'Black holes' follows the same rules as Chess, with two exceptions: the difference in board beeing less essential, new piece called 'hole' and its interplay interplay with other pieces is the real change. These differences are all described in the following rules.

Board and starting setup

The board is rectangle-shaped 5x8, it means you need only to forget about f-h files on normal chessboard. The lower-right square is black (although it is not important). Here it is together with original setup (white pieces capital case, black pieces lower case, k - king, q - queen, b - bishop, r -rook, s - knight, p -pawn, below is also used h - hole):

    8   | r |:s:| b |:q:| k |
    7   |:p:| p |:p:| p |:p:|
    6   |   |:::|   |:::|   |
    5   |:::|   |:::|   |:::|
    4   |   |:::|   |:::|   |
    3   |:::|   |:::|   |:::|
    2   | P |:P:| P |:P:| P |
    1   |:R:| S |:B:| Q |:K:|
          a   b   c   d   e   


Only 7 different pieces appear in the game - 6 normal pieces and holes. All normal pieces move normally, as an addition they can do special moves in interplay with holes as described below. Castling, promotions and e.p. captures are allowed.

It is convenient to use flat checker pieces for holes.


White begins, the moves are played alternatively by both sides.

Instead of move, both sides can drop own hole to any vacant square on its base rank. (It is possible to parry check on last rank this way by cutting check line.) Both sides can have any number of holes on the board. The hole cannot be taken by normal move of any piece. It moves as a king and normally doesn't capture. It means normal move of hole is 1 square ortogonally or diagonally to vacant square and normally it doesn't give check.

Pawn can promote to hole on last rank. Anytime pawn is on second rank it can make double step.

All pieces including holes, but except king, can play move entering hole of own side and leaving hole of own side too, piece leaves latter with added energy, it means it can make longer move and capture any piece including opposite holes and all own pieces. Entered hole is called 'black hole' and left hole 'white hole' below, such move can be called 'relativistic' as it breaks rule of preserving energy :-)

The more precise rules of relativistic move are the following:

The piece X making relativistic move makes normal move to square where its side has hole - 'black hole' - as if this square was vacant or occupied by enemy piece (these are different conditions for X beeing pawn or hole!). Remember the direction in which X entered 'black hole' Then player chooses any own hole (not the hole that made the first part of relativistic move if X is the hole) the move to be 'white hole' (during the relativistic move non-moving hole can be both 'black hole' and 'white hole'). Piece X is moved to square occupied by 'white hole'. Then the piece X must make move in the same direction in which it entered 'black hole', this time the move leaving 'white hole'. But this second move can be any multiple of X's normal movement in the same direction, provided all intermediate squares on the line of move from 'white hole' are vacant, and at its final square piece X can capture any piece including own pieces (but excluding own king) or holes of both sides. (It means, e.g. knight leaving 'white hole' moves as a nightrider in given direction.)

There are two understandable conditions for pawn making relativistic move:

  • if first part of relativistic move of pawn was ortogonal movement, second part mustn't capture (as pawn doesn't capture ortogonally),
  • if first part of relativistic move of pawn was diagonal movement, second part must capture (as pawn must capture makig diagonal move). It is possible for this second part to be e.p. capture of pawn that just did normal double-step over square where it could be captured by pawn making relativistic capturing move.
Also pawn ending its relativistic move on last rank promotes immediately.

King cannot make relativistic move. Of course, threat to capture the opponent's king by relativistic move is check.

The goal of the game is to checkmate the opponent's king.

See below examples of relativistic moves.


The notation I use for 'Black holes' shows the different spirit of three kinds of possible moves: normal moves of any piece, drop of hole and relativistic move of any piece:
  • normal move of any piece, including hole, is written in shortened algebraic notation, e.g. 1.e4 a5 2.Ke2 Ra6 can be the beginning of the game,
  • drop of hole is written in parenthesis, it consists of character H and square where drop appears, e.g. the game above can continue 3.(He1) (Ha8) 4.Ke3 Ha7 5.He2 Hb6 6.Hd3 Hc6 (now white cannot play 7.Ke4 as this would set white king into check by relativistic move of pb7),
  • relativistic move is written in 'extended' algebraic notation, it consists of sign of piece making relativistic move (sign p for pawn is omitted, of course), its departure square, dash, 'black hole' square, dash, 'white hole' square, dash or 'x' depending on character of relativistic move (normal move or capture), arrival square. E.g. game above can continue 7.d2-d3-d3-d6 Ra6-c6-c6xd6 8.Qe2 Sb8-c6-c6xe2.

Examples of relativistic moves

Consider situation on next diagram:

    8   | r |:s:|   |:q:| k |
    7   |:p:|   |:p:| p |:p:|
    6   | B |:p:| h |:h:|   |
    5   |:::|   |:::| h |:H:|
    4   | H |:P:|   |:::|   |
    3   |:::|   |:::| S |:::|
    2   | P |:B:| P |:P:| P |
    1   |:R:| H |:::| Q |:K:|
          a   b   c   d   e   
1. Ra1 can make 3 relativistic moves:
  • Ra1-b1-b1-c1 (black hole b1, white hole b1)
  • Ra1-b1-b1xd1 (black hole b1, white hole b1)
  • Ra1-b1-a4xb4 (black hole b1, white hole a4)
Note that two parts of relativistic move are always in the same direction.

2. Bb2 can make 3 relativistic moves too:

  • Bb2-e5-b1xc2 (black hole e5, white hole b1)
  • Bb2-e5-a4 -b5(black hole e5, white hole a4)
  • Bb2-e5-a4xc6 (black hole e5, white hole a4)
Remember that opposite hole can be taken only by relativistic move.

3. Knight and pawns are very strong pieces on its starting square provided they cooperate with holes! Only one white pawn which isn't 'en prise' in this position:

  • pa2 can be captured by two black pawns: d7-c6-d5xa2 or e7-d6-d5xa2
  • pb4 can be captured by these two black pawns too: d7-c6-d6xb4 or e7-d6-d6xb4
  • pc2 can be captured by hole: Hd6-d5-c6xc2
  • pd2 can be captured by knight: Sb8-c6-c6xd2

Illustration games

These games were played by me and my friends after I invented the game. They show many points of game I already noted and some others I didn't spot at all. :-)

Exercises for interested people

Hopefully no one will ruin my solutions by finding new possibilities. All questions are connected with the following position:

    8   | B |:s:| k |:q:| b |
    7   |:::| h |:r:| p |:H:|
    6   |   |:h:| h |:h:| p |
    5   |:p:|   |:p:|   |:H:|
    4   | H |:::| P |:::| P |
    3   |:P:| R |:::|   |:::|
    2   | P |:p:|   |:P:|   |
    1   |:::| Q |:H:| K |:S:|
          a   b   c   d   e   

  1. Black can check white king by normal move threatening relativistic knight move. How can white prevent such check moving any of four pieces on base rank (Q, H, K, S)?
  2. Both sides can set mate in 1. How?
  3. It is possible to prove that some pieces in this position already passed holes in the previous course of the game. How many pieces did surely make relativistic moves?
Do you want to check your own solutions? Are you giving up? Look at the intended solutions.


Mail me any questions about 'Black holes', I'll be happy to answer them. My adress: (email removed contact us for address) My website is dedicated to chess problems, mostly fairies, it is known as Chess Composition Microweb.
Written by Juraj Lorinc.
WWW page created: August 23, 1999.