Wizard of Oz Octal Chess

On résiste à l'invasion des armées; on ne résiste pas à l'invasion des idées. --Victor Hugo

Wizard of Oz CVs are based on designating certain squares for special effect in what variantists call a Mutator. Here in change of Rules for 64 squares there are four Yellow Brick Road squares. They are c3-d4-e4-f5. When on one of those, a piece or Pawn moves only by way of intermediate Tornado square reachable by normal move. The first provisional leg temporarily onto Tornado square has no effect except to enable the second leg completing the bipartite Move. In essence double move is required from YBR, but no capturing permitted on the first leg. The pass-over, or leapfrog, or formally Tornado square can equally be occupied by own unit but not vacant.

Standard Wizard of Oz on conventional 64 uses Rook, Knight, Bishop, and Pawn as usual. Rules below specify Pawn mode on YBR and specifics of King and Queen manner there.

Who was world Chess champion when Baum published first of fourteen WoO books in 1900? Lasker. Who was champion upon the 1939 film release? Alekhine. The movie is based to reasonable extent on the original 1900 book but does not try to cover everything. What does Oz's Yellow Brick Road have to do with Chess? Allegory, morality, spiritual growth. Insofar as unelaborated 64-square Chess presents less challenge nowadays (think Scarecrow seeking mental growth or Lion courage), here is one exegetic statement: Symbolism, not overdrawn regarding popular film more than the book.

Setup

Same, and for Wizard of Oz character it goes: Tinman-Lion-Scarecrow-Witch-Wizard-Scarecrow-Lion-Tinman. The rows of Pawns stand ranks 2 and 7. The Yellow Brick Road four spaces are to be fixed each and every given game of course, but should be experimental in the long run as to better preferred exact locations. See Notes on how many possiblities there can be. Particular 'c3-d4-e4-f5' squares should work fine as recommended to be marked Yellow, deliberately asymmetrical. Putting them more on White's side is intended to counterbalance White's first-move advantage.

'U' is not used much yet for a piece-type, so the initialed line-up WoO-style can be T-L-S-U-W-S-L-T, where U is Wicked Witch, called Witch for short.

Pieces

All six piece-types have standard move methods when not on YBR.

On Yellow Brick Road, Wizard also moves by Tornado effect. In addition, Wizard alone can step along but not off YBR without Tornado intermediate square. That is, along c3-d4-e4-f5 Wizard can one-step the route in a Move freely, or use Tornado invervention when another piece or Pawn is adjacent. He has both choices, but cannot move directly off YBR; there has to be provisional square available having other piece or Pawn already on it.

No way for anyone to get off YBR without a "leapfrog" square already occupied -- except Witch. Witch, moving like Queen on regular squares, does not utilize the Tornado effect at all and so never makes the double move (Mutator). When on YBR, Witch must move along YBR any distance including off the YBR the same radial direction. In this regard then, Witch is unlike all the other pieces including Wizard(K). For example, Witch on d4 can go in two directions: c3 and onward, or e4 and onward. When on c3 or on f5 Witch has only one direction, and it is fine of course to go just one step to another YBR square. In general, player wants to keep Witch off YBR because the piece alone is clearly impeded there, losing options.

Rules

Another Yellow Brick Road square can create the Tornado intermediary if a piece or Pawn stands there.

Pawn gets its intermediate Tornado spot by regular non-capturing one-step. For example, White Pawn on d4, a YBR spot, faces a Black Pawn on d5. 'd5' then is Tornado cell for the d4-Pawn and from there provisionarily it can capture at either c6 or e6 to complete the single Move, or freely move to d6 if d6 is unoccupied ending its turn that way. It more or less steps over the other Pawn from d4 to d6.

For Tornado effect by Pawn's one diagonal capture mode, the square creating the effect must be occupied by opponent piece or pawn other than the King. That piece on the Tornado square is not captured, but just enables the Pawn to go on.

Zero, Betza's Rule Zero is convenient reference for interpretation of natural Stalemate, en passant, Checkmate, repetition of position and the rest. Turns alternate until Checkmate.

Notes

This article can be read in conjunction with Wizard of Oz Decimal Chess, Decimal_Form, a 10x10 Chess Variant for fuller perspective or different wording.

It is possible to play subvariants with from 2 to 6 Yellow Brick Road squares, but four seem ideal for clarity and challenge and are recommended. Assuming use of four Yellow Brick Road squares on 64, how many possible locations are there?

Full allowance is 32*31*30*29 or 863040, almost a million. However, we generally want to exclude those combinations of four from among the thirty-two squares a3 to a6, b3 to b6...h3 to h6, that make for isolated squares not adjacent to the other two or three squares in the YBR. As well, we want to exclude what can be called "double adjacencies" like 'c3-c4-d4-e5' as inelegant. However, diamond patterns like e4-d5-e6-f5 are more feasible and are included in tallying the number of four-special-squares locations below.

The calculation is not as much of a "snap" as Fischer Random Chess 960 for example fitting its particular bill for backrank: Bishops opposite cell-color etc. But I arrive at that there are 456 possible Yellow Brick Roads of four spaces as described on 64 squares -- that is, omitting both double adjcencies and no adjacencies. Fuller explanation with computation, summing all the better cases, will follow here or in Notes of the next Yellow Brick Road Wizard of Oz CV.

And theory of effect of location of YBR on White First Move Advantage not yet started is to be addressed. Fundamentally it is held forth that White-Move will have geometrical interpretation! Some arrays from among the 400+ set-ups on 64 will fully neutralize WFMA. Preliminarily particular 'c3-d4-e4-f5' could well be one of the best "neutralizers." This makes it essential to include certain squares delivering a certain function as being part of so-called "Array." That function is precisely the Yellow Brick Mutator restricted to just a few spaces, requiring Double Move. A game cannot begin until you set up both the pieces AND the squares.

Going further from the general to the particular, in the recommended set-up array, having c3-d4-e4-f5, White from the starting line-up can step any of three Pawns and one Knight to a Yellow Brick Road cell, whereas Black can do so with only one Pawn. Is that as claimed and likely a slight White disadvantage? Yet to be proven.