You are on the backup site for Any posts, moves, or other changes you make here will not be permanent, because the pages and database from the main site will be backed up here every midnight EST. Additionally, things may not be working right, because this site is also a testbed for newer system software. So, if you are not here to test, develop, or merely read this site, you may want to change .org to .com in the navigation bar and go to the main site.

The Chess Variant Pages

This page is written by the game's inventor, George Duke.

Wizard of Oz Decimal Chess

A comment last week describes new CV based on Wizard of Oz Yellow Brick Road. It runs the rest of this Introduction except couple added sentences at end of Introduction. This CV has new Mutator. Wizard of Oz is a decimal variant rated G, reluctantly leaving out a feature for a later subvariant. You've heard the Communist interpretation of the 1939 film after the 1900 book: History.

That is, for starters Strawman is agrarian proletariat and Tinman industrial worker and Emerald City utopia. Now the line-up is: Tinman-Lion-Scarecrow-Toto-WW-Wizard-Toto-Scarecrow-Lion-Tinman on 10x10. All pieces move as usual except WW(Q) and W(K) on YBR. The Yellow Brick Road runs six spaces diagonally connected but one orthogonal adjacency, h3-g4-f5-e5-d6-c7. The other correspondences are Scarecrow/Bishop, Lion/Knight, Tinman/Rook. Ten regular Pawns represent citizens of both Oz and Munchkin, but subvariants could separate their powers.

There is not WoO CV til this one, though there are WoO Chess sets, Sets.

There are CVs with both "Wizard" and "Witch" in title. Nahbi is coincidentally only a few spaces from Nemeroth in the alphabetical index, since Lawson mentions non-General Nemeroth; the protypical 'G' rating in that index would be allegorical Wizard of Oz, ran the process, innocently actual tract for socialism to rein in earlier billionaires and environment travesty -- whoa Rated X, G is X. Piece, paired Toto is Nahbi in this first WoO CV, and others may experiment with different p-ts to go with the standard six RNBKQP. Toto as dog is appropriately Nahbi because in Korean "nahbi" means Cat, hence dog equals cat.

Normal Rules for capture and checkmate, so how does the YBR work? When piece/pawn is on one of the six, its Move is bipartite. First it must make its move onto the same square as another unit (the new Mutator) of either color momentarily. There is no effect in the temporary co-occupancy. Then its actual completed Move is from that temporary spot by way of (another) normal move in any direction. The completed move either occupies vacant square or captures opponent on arrival square, just like any regular move when not on YBR. The two legs are one single Move. When not on YBR there is just the one usual Movement or leg of its piece-type. This Mutator solves the too-great-spacing problem always apparent on ten by ten.

The provisional cell must be available from the YBR location, otherwise it cannot move at all. In general, being on one of the designated central YBR six expands greatly the number of options, the move tree. The fact of asymmetry in location of the six squares makes for interesting ongoing experimentation; initially maintained is that it slightly disadvantages first-mover White to have the Road closer to her, bringing about balance towards true equality.

This Mutator is kin to the pair of CVs Duniho's Extra Move and Bonham's Option Chess in giving more choices, but it works by spacing not the number of Move it is (Extra Move is already open-ended but subvariants could be more restrictive). On dwarven 64 make the YBR simple c3-d4-e4-f5.

The Wizard, as King, also can move along, but not off, the Yellow Brick Road without an intermediary to sit on temporarily. And Wicked Witch, as Queen, does not do the provisional step at all, but is forced, when on one of the Yellow six as departure, to move regularly at least one step along that YBR then continue same direction (so WW is plainly impeded by YBR, losing choices). The only piece always retarded by being on YBR is the Wicked Witch. But the Wicked Witch is still of more value than the Tinman probably an operational 5 to 6 or 6.5.

At once we potentially solve all three: (1)Spacing on decimal; (2) Computer dominance by entering enlarged move tree; (3) White first-move advantage by trials positioning the six special squares.



The bipartite Move from ybr is of course progressive two-step, no back-step whence it originates, and no null move. This CV is basically a Mutator-CV because pieces and movements are the same, but the Mutator, operating directly on the pieces when they are on the Yellow Brick Road, changes everything about the play.


Rook-Knight-Bishop-Nahbi-Wicked_Witch-Wizard-Nahbi-Bishop-Knight-Rook. The same line-up takes on a full Wizard of Oz character as 'Tinman-Lion-Scarecrow-Toto -WickedWitch-Wizard-Toto -Scarecrow-Lion-Tinman'. The ten pieces either way they are called stand in starting array back-ranked Row 1. Ten Pawns Row Two complete White's starting material, and Black's correspond as usual.


Rook, Knight, Bishop, King and Queen have their normal rules of movement. However, King and Queen as respectively Wizard and Wicked Witch have a difference on the six Yellow Brick Road squares that is explained under Rules and was described in the comment link.

The Pawn's movement needs to be described separately too because standard Pawns are what variantists describe as divergent, moving and capturing differently. That quality of Orthodox Pawns needs clarification with respect to the six special Yellow Brick Road squares.

In place of Nahb1i/Toto , the first of the four fundamental Chess pieces can be utilized, namely multi-path Falcon. Falcon has qualities of all the other three basic chess pieces, R, N, and B, and is the template from which they derive. Since Nahbi(Toto) has the Knight's movement, as well as Zebra's arrival square, it's just as well to make "R-N-B-Nahbi" the standard Wizard of Oz chess variant. That is, it takes more advanced chess skill to play Falcon effectively, whereas Nahbi is at least half familiar to everyone. It's enough getting used to the new Mutator. Other recommended alternatives for Nahbi are in Notes for possible subvariants below. The key to this CV is the Mutator not the pieces per se, since the Mutator can apply widely to other existing CVs. The YBR Mutator can even apply to small 64 squares with Orthodox RNBKQP.

Mainly on good size 10x10, just use the additional paired piece, next to Wicked Witch and Wizard in the opening back rank, as having the power of either Nahbi or of Falcon. Both will make for interesting play with the ybr Mutator brought about by the location of six special squares. Just determine at the start of play which method of movement is designated to use the particular game, Nahbi or Falcon for the extra piece-type comprising full-size board 10x10.


Betza's Rule Zero for all important auxiliary factors applies naturally: Checkmate, Stalemate, repetition of position, en passant and so on. Unlike vast majority of decimal CVs pawns have just one- and two-step options from array.

On 10x10 the six special squares, collectively called the Yellow Brick Road, are h3, g4, f5, e5, d6, c7. Here is the comment again how those squares work: Yellow_Brick_Road.

So no piece or Pawn can step directly off the YBR. It must have a provisional square first to step off and situate on for a moment, then make another regular move from there. That is the new Mutator and it applies only on YBR. We may as well call any provisional square a Tornado square. That just means any square reachable by a piece or Pawn from the Yellow Brick Road that is in fact already occupied by another unit: Tornado Square, or leapfrog square. When there is not such a square available, a piece is stuck on the ybr location a while.

Pawns can have Tornado square using one-step diagonal mode only if it is an opposite color piece or Pawn other than King(Wizard) on that square. But using one-step non-capture mode, there can be any piece of either color including King creating the Tornado effect.

Wizard alone on YBR can one-step to another YBR cell without a Tornado square. Wicked Witch alone never moves by Tornado intervention, and when WW is on YBR has only one or two possible directions to travel, those starting along YBR and continuing any distance.

Turns alternate after White opening until Checkmate. YBR squares and subordinate Tornado squares can create some interesting patterns for Check and Checkmate as the game progresses.


For clarity there are six YBR squares on 10x10. Anywhere from 5% to 10% of the squares being ybr locations would seem to be effective, if wanting to develop subvariants a little different. Theosophy.

This 'user submitted' page is a collaboration between the posting user and the Chess Variant Pages. Registered contributors to the Chess Variant Pages have the ability to post their own works, subject to review and editing by the Chess Variant Pages Editorial Staff.

By George William Duke.
Web page created: 2015-08-25. Web page last updated: 2015-08-25