By Jörg Knappen
The name of the game
This variant is named after the strongest piece it features: The Pentere or Quinquereme, combining the moves of FIDE Queen and Quintessence.
Quinquereme Chess is played on a 12 times 12 checkered board. The lower left corner is *white*. Queens and Penteres are on squares of their respective colours.
The opening setup
In the first rank:
Zebra, empty file, Quintessence, empty file, Leeloo, empty file, Pentere, Leeloo, empty file, Quintessence, empty file, Zebra.
In the second rank:
Camel, Rook, Janus, Knight, Bishop, Queen, King, Bishop, Knight, Janus, Rook, Camel.
In the third rank, there are 12 Pawns.
The pieces in the second rank are fairly standard.
The Janus combines the moves of bishop and knight.
There is no castling. Instead of castling, the King has the privilege of a King's jump in its first move. It may jump to any free square in the back two ranks. To perform the King's jump, the King must not be in check. Since it is a true jump, the King may jump over attacked squares.
The pieces in the first rank are:
The Zebra is a (2,3)-leaper, it moves one square straight and two squares diagonally, jumping over any obstacles like a knight. The Zebra is the weakest piece in Quinquereme Chess, but it can attack any other piece without being directly counterattacked.
The Quintessence performs consecutive knight moves with a turning angle of 90 degrees in a zig-zag pattern. It is featured in Quintessential Chess and in Nachtmahr. Since there is a queen in the game, the Quintessence is notated with the letter V (roman numeral five).
The Leeloo combines the moves of Quintessence and Rook. It was first featured in Quintessential chess.
The Pentere (or Quinquereme) combines the moves of Queen and Quintessence.It is named after an ancient galley propelled by five rows of oars, Pentere is the greek name, Quinquereme the latin version of it. It is notated with the letter P.
The Pawns move and capture like FIDE Pawns, with the exception that they also may make a triple step as their first move. They may be captured en passant by an opponent's Pawn as if they made a single or double step.
The further the Pawns advance, the more and stronger their promotion choices become.
After reaching the 9th rank, they may promote to Zebra or stay Pawns.
After reaching the 10th rank, they may promote to Zebra, Camel, Knight or Bishop or stay Pawns.
After reaching the 11th rank, they may promote to any of the pieces mentioned before or to Rook, Quintessence or Janus, or stay Pawns.
After reaching the 12th rank they promote to any of the pieces in the initial setup (except King, of course).
Aim of the game
Checkmate the opponent's king. If you carelessly stalemate your opponent, you loose (like in Duke of Rutland's Chess).
Draws may occur by insufficient mating material or by threefold repetition of the same position.
There is no 50 moves rule. The players should agree on the outcome of the game. If they cannot agree (in a tournament) a referee decides.
The two front lines of the initial setup are identical to the Janus Kamil Chess setup. This is a rather conservative setup and the first opening moves aren't too far away from standard opening lines. The more exciting and innovative pieces are added in the first rank.
In the initial setup, all Pawns are protected. In the second rank, all pieces except the rook and the knight are protected. By developing the knight one can easily protect the starting squares of rook and knight, too. The Quintessential pieces are well hidden and cannot jump out immediately.
Use the King's jump to secure your King's position and build a fortress around your king -- but at the same time, don't forget about developing your pieces.
There are three kinds of lines to watch: Straight lines (Rook lines), diagonals and quintagonals. In order to defend the king, a strong castle in one of the corners is necessary. At best, keep the places a knight move away from the king occupied to block quintagonal lines.
The game contains 13 pieces of different strength, from the very weak Zebra to the superpower Pentere. However, the weakest piece can attack the strongest without being counterattacked. The Zebra has a lot of forking power, too.
It may come out as a surprise, that the colourbound Camel is stronger than the unrestricted Zebra (This fact is suggested by end-game analysis of endgames with fairy pieces, link to ...). An explanation of this fact can be found in Jeliss' article on the Knight tour: Knights and Camels have more round trips consisting of 6 moves than general skew leapers (like the Zebra). This additional maneuverability makes them stronger.
JÖrg Knappen: Nachtmahr
JÖrg Knappen: Quintessential Chess
JÖrg Knappen: Janus Kamil Chess
Duke of Rutland's Chess
X X: Endgame Statistics with Fairy Pieces
Jeliss: Knights Tour