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This item is a game information page
It belongs to categories: Orthodox chess, 
It was last modified on: 2000-10-23
 By David  Paulowich. Unicorn Chess. 10x10 variant with a new piece that moves as a Bishop or a Nightrider. (10x10, Cells: 100) [All Comments] [Add Comment or Rating]
Kevin Pacey wrote on 2018-03-01 UTCExcellent ★★★★★

You just have to love those Unicorns!


David Paulowich wrote on 2004-12-03 UTC
Lions and Unicorns Chess: Inventor's Comments <p>The Game of Jetan or Martian Chess is highly original. I was especially impressed by the way 8 'Pawns' (Panthans) and 12 stronger pieces were placed in the initial setup on a 10x10 board. Eventually I came up with the idea of placing the Knights on a2, j2, a7, j7 on a 10x8 board. This gave me room to place LRCBQKBURL on the first and eighth ranks. While the Knights may take longer to reach the central squares, they do have the option of leaping to the fourth rank on their first move. Castling still involves moving the king two squares towards a rook and then leaping the rook over the king. But there really is no safe place for your King on the board when the opposing army has 4 powerful leapers added to the standard 16 pieces! You can expect short games with sharp tactical play. <p>Piece values will be different than those I proposed for Unicorn Great Chess, as the board is smaller. Pawns are more dangerous when there are only eight ranks. I have decided to limit Pawn promotion to Chancellors, Queens, and Unicorns (only) in all three variants with Unicorns. PBM presets for Unicorn Great Chess and Lions and Unicorns Chess are available for use. Enjoy!

David Paulowich wrote on 2004-08-01 UTC

Unicorn Great Chess: Inventor's Comments

I am pleased to see the PBM Preset for Unicorn Great Chess is still available on this website. I had been planning to post a rules page with a Zillions game file several years ago, but did not get around to it before my hard drive crashed. Anyway, here are some brief notes on this variant.

Unicorn Great Chess adds four 'Lions' to the board - on the second and ninth ranks. The Lion is identical to Ralph Betza's 'Half-Duck' (HFD, a piece that can move one square diagonally or jump two or three squares orthogonally), from the Remarkable Rookies army. It was designed to be at least as strong as the Rook on the 8x8 board, but it will be weaker on larger boards. I chose the name Lion as a reminder of the 3-square leaper in Grande Acedrex (1283). That game also has a piece called the Unicorn (or Rhinoceros). The remaining ten White pieces are arranged CRNBUKBNRQ on the first rank. Placing the Chancellors and Queens in the corners (with the Pawns in front of them also defended by the Knights) is an opening setup I have used on 64, 80, and 100 squares.

My somewhat rusty memory tells me that a King and Lion can force checkmate against a lone King. 'A Pawn promotes to a Chancellor, Queen, or Unicorn of the same colour upon reaching the player's tenth rank.' Perhaps I should amend that rule to also allow promotion to a Lion, if desired. Note that the Lion has the longest 'single leap' of any piece on this board, which makes it capable of delivering a Fool's Mate: 1. Lion f2-f5, Lion f9-f6 2. Pawn e3-e4, Lion f6-f4 (mate)

My suggested game values (allowing for Pawns being a little weaker on the 10x10 board) are as follows: Pawn 100, Knight 300, Bishop 350, Lion 450, Rook 550, Chancellor 900, Queen 1000, Unicorn 1000. [EDIT] I decided to bump the Lion up to 500, see the Rules section on my Unicorn Great Chess page.

I firmly believe that Q = R+B+P and Q+P = R+R on 64 or 100 squares. My (limited) playing experience on 64 squares leads me to conclude that a Chancellor is worth a Rook and Knight and half a Pawn. So I used that formula to calculate a 900 point value in this game. WARNING: the Lion and Unicorn values are mostly based on guesswork. It certainly would be convenient if the Chancellor was worth exactly two Lions (or a Rook and a Bishop). Other, more experienced, chess variant players may come up with different values. --- David Paulowich


Michael Nelson wrote on 2004-07-30 UTC
Ralph Betza's work suggests doing mobility conditions based on about 60% of initial piece density. This is 30% for FIDE Chess and 26.4% for Unicorn Chess. If Ralph is correct and this is the best value for overall mobility ratings, the Unicorn is measurablly stronger than the Queen with respect to mobility, as break even occurs at 22% piece density. One overlooked Queen advantage that tends to even out the non-mobility evaluation factors: The Queen has the King Interdiction ability and the Unicorn lacks it. King Interdiction refers to the ability of a Rook (or any piece having a Rook's move) to confine the enemy King to a certain section of the board by attacking the entire length of a rank or file so that the King cannot cross it.

Greg Strong wrote on 2004-07-30 UTC

These values may well be closer than mine, but I'm having a hard time believing that the Queen is worth more than the Unicorn. At the beginning of the game, the board is 44% full, and at that point the Unicorn has an average mobility of 14.18, compaired to only 12.36 for the Queen. Now, as pieces get traded off and the board clears out, the mobility of the Queen goes up a little faster. The average mobility of the two just happens to break even when exactly half the pieces are gone (board 22% full). And with even fewer pieces, the Queen begins to develop a small mobility advantage.

But, of course, there's more than mobility. I think other factors favor the Unicorn as well. The Queen attacks in 8 directions, whereas the Unicorn attacks in 12, giving it more forking power. Also, of the Queen's 8 directions, only 3 of them are forward. The Unicorn has twice as many forward attack directions (although 2 of them have a rather shallow slope.) Finally, there's stealth. The Unicorn's attacks along Knightrider lines is stealthy, meaning pieces attacked this way cannot counter-attack, with the exception of the Knight.

Presumably, the Queen has advantages, too. The forward Rook-slide is a very nice move because of it's ability to coordinate with the move of the pawns, and the Unicorn lacks this move. Any other Queen advantages I'm overlooking?

If anyone is interested in running a test, I think we can with the Game Courier. You take 2 Queens, I'll take 2 Unicorns ...


Roberto Lavieri wrote on 2004-07-30 UTCExcellent ★★★★★
Unicorn Great Chess is excellent. I think the table of value conversions given by Moussambani is, gross speaking, correct. Unicorn value is a bit less than that of a Queen, and in a 10x10 Board the Queen value is more or less the same of two Rooks or three minor pieces. Lion value is approximately the same of the Bishop value, and it is higher than the Knight value.

Moussambani wrote on 2004-07-29 UTC
I don't know if those values are right, but I like how they give nice trades. N+P = B N+P = L B = L N+N = R N+R = C B+R = U L+R = U C+P = U N+C = Q R+R = Q N+N+R = Q And also... N+B = R+P N+L = R+P N+B+B = U+P N+B+L = U+P N+L+L = U+P R+C = N+Q N+B+R = Q+P N+L+R = Q+P etc As well as these close calls N = P+P+0.5 R = B+P+0.5 R = L+P+0.5 C = N+B+P+0.5 C = N+L+P+0.5 Q = N+B+B+0.5 Q = N+B+L+0.5 Q = N+L+L+0.5 B+B+L = Q+0.5 B+L+L = Q+0.5 A game with that many trade options sure looks interesting!

Anonymous wrote on 2004-07-29 UTCExcellent ★★★★★
I like Unicorn great Chess too, my suggested values are: Knight: 2.5 Bishop: 3.5 Lion: 3.5 Rook: 5 Chancellor: 7.5 Unicorn: 8.5 Queen: 10 The value of the Queen is augmented in a 10x10 board, and I think its value is more than the Unicorn.

Greg Strong wrote on 2004-07-29 UTC

I like this game a lot (or more particularly, the Unicorn Great Chess which doesn't have a page yet.) I have been thinking about how the pieces should be valued, and here is my suggestion:

Knight - 2.5
Bishop - 3.5
Lion - 4
Rook - 5
Chancellor - 8
Queen - 9
Unicorn - 9.5


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