Bachelor Kamil combines ideas from two ingenious variants elsewhere on these pages: Doug Chatham's Bachelor Chess and Wayne Schmittberger's Wildebeest Chess.
It builds on similarities between the two, such as putting the Bishops side by side. It also takes a middle line where they differ, with the numbers of both ranks and files the average of the two.
The term "Kamil" literally means completed, and is applied to variants in adding an extra piece to an otherwise traditional array. As the extra piece is often called a Camel this makes for a nice pun in several languages. It is the characteristics taken from Wildebeest Chess, which certainly qualifies as a "Kamil" form of modern Chess, that make the epithet appropriate for this game.
The board has 8 ranks numbered 1 to 8 and 9 files
lettered A to I.
The array has the same pieces as FIDE Chess except with an extra Pawn, no Queen, and two Camels in the modern sense. Rooks and Knights can be differentiated as Camel-side and Bishop-side, and Bishops and Camels as inner and outer. "Castling either side involves the King moving to the home square of the outer piece (observing FIDE rules about check) and the Rook to that of the inner one."
I noticed that I did not specify in the original rules whether the armies were aranged with rotational or reflective symmetry. As Wildebeest Chess has the fortmer and Bachelor Chess the latter there are effectively two alternative arrays:
The Camel's move can be expressed as three steps in one orthogonal direction (as against the Knight's two) and one at right angles; as two steps in one diagonal direction and one at right angles; or as two Knight moves at right angles. Whichever way you see it, the intermediate squares need not be vacant.
The Gnu, or Wildebeest (these being alternative names for one of Africa's many ungulates), combines the Knight and Camel. Like the King the Gnu can triangulate - return to its square in 3 moves by describing a right triangle comprising 2 of its shorter moves and 1 of its longer one.
Pawns still have an initial double move and the en passant rule. They can be promoted to other pieces occurring in the array, but they can also be promoted to a Queen or to a Gnu.
The word "mate", both as noun and as verb, has other meanings outside Chess, and an extra way to win is to find the King a "mate" in the sense of "partner, companion, esp. spouse". This happens by promoting a Pawn to Queen and reaching a position where a Queen is adjacent to the King.
Here I note that "mate" is also an anagram of "tame", so I also allow a win by taming not a Shrew (for those who know their Shakespeare) but the much Wilder Beast that the Gnu is evidently judged to be. Likewise this is achieved through a position in which King and Gnu are adjacent.
Additionally the King must not himself be in check.
I am open to thoughts on whether a "Medinese marriage" (Queen next to King but in imminent threat of capture) or "Medinese taming" (Gnu likewise) should count as a win for the player who has brought the pieces together (Doug Chatham's preference) or whether the game can continue provided the capture takes place. Note that there is no question of it being a win for the player threatening the Queen or Gnu as these are both capturable pieces.
Of course if you can get your King next to two of either piece or one of each it is an indisputable win whether neither, one, or even both are threatened, as they cannot BOTH be captured in one move. "But that's bigamy!" I hear you cry. To which I can only emulate the decadent hero of Ralph Betza's Captain Spalding Chess, and reply: "It's big o' me too!".
I have also featured the Win by Marriage idea in my 4-player variant BacCanCat, as well as in subvariants of Simple Tunnelchess and Recapitulative Chess.