Pieces are never attacking friendly pieces or I miss something

That is the answer to my question. So if a virgin King is on h1, a black Bishop on h2, and a black Knight on g4, the King can move to h3. If his own Bishop was on h2 instead, he could not.

Some people would say pieces can attack the square a friendly piece is on. They obviously cannot capture it, but that doesn't necessarily mean the same thing as being attacked. E.g. when my King stands next to an enemy Pawn that is protected, does he attack that Pawn?

Personally this rule strikes me as quite illogical; to pass through a square it should be empty, and if you don't pass through it but jump over it, you shouldn't have to worry if you are attacked there. And I wonder how much this rule actually affects the game; it seems very hard to attack any squares next to the enemy King before he moves away to safety, as he starts buried behind 2 or 3 ranks of pieces. Especially if he can jump.

In general I like your variants a lot, because you do not only feature super-strong pieces (much stronger that Rook), but also Knight-class pieces. Most variants suffer from an over-abudance of Queen-class pieces. The middle of the strength spectrum is still a bit under-populated, though: almost none of the pieces is close to a Rook in value.

This variant has some funny rules that required special attention. One was promotion: not only Pawns promote, but a Prince reaching last rank can optionally promote to Queen too. And a Ship can promote to Griffon in the last-rank corners. This was handled by defining Prince as first piece, and specifying only one promoting piece, with as only choices Prince and Queen. This invokes the normal promotion procedure for Princes, letting the user select from the legend table.

Pawn and Ship make use of the user-supplied JavaScript function WeirdPromotion. This automatically promotes these pieces when they reach their respective zones, as in this cases there is no promotion choice.

Another unusual feature of this variant is that, when checkmated, Kings can swapped with Princes,wherever these are located. To make the diagram indicate this possibility, the King was equipped with a universal-leaper move U. The modality 'x', which was already introduced on non-final legs of multi-leg moves to indicate relaying of powers, is now used for indicating such a piece swap with a friendly piece on final (or only) legs.

Adding a plain xU to the King moves would allow it to be swapped with any friendly piece, however. To single out the Princes, we declared the board to be zonal by providing a JavaScript function BadZone. This function tests the the target location for containing a piece of the same color as the mover, and declares the to-square invalid if a non-Prince if found.

Centennial Chess

This is another chess variant that is quite popular on this site. In contains the innovative feature of an asymmetric piece (the Rotating Spearman) that can change its orientation at the end of its turn, deciding how it will be able to move the next time. It also contains several other unorthodox pieces, and thus makes a grateful subject for presentation as interactive diagram:

Spearman orientation

The main challenge here of course was to implement the re-orietation of the Spearmen. This required some extra scripting, through one of the standard 'hooks' of the basic diagram script, providing the (optional) function 'WeirdPromotion'. Because the re-orietation of the Spearmen is treated as promotion of one piece type to another, where Middle,Left and Right Spearman are defined as three different piece types.

To make this work satisfactorily, the basic JavaScript powering the diagram had to be enhanced a bit, because it was necessary to make WeirdPromotion invoke the promotion procedure normally used in wester Chess variants, where you can select the promotion piece from the table by clicking there. Before this WeirdPromotion wasonly used in Shogi variants, where there is no choice other than to promote or not. The was solved by making the choice of the (normally non-existent) piece number 1022 indicated by WeirdPromotion be interpreted as a wildcard, allowing the user to select the actual piece from the table. Since WeirdPromotion (when supplied) is called after every move, it just has to test whether the moved piece is one of the Spearmen orientations, and if it is, wait for the user to select the new orientation.

To make this selection of new Spearman orientation easier, the table of pieces is printed next to the board permanently, rather than in the default way as an initially collapsed table under the board. Placement of the table anywhere in the page can be achieved by defining a HTML element <table id="pieceTable"></table> in the desired location.

Castling

Castling was also a bit problematic in this variant, because the King moves a different number of squares on the King side and Queen side. While the setup is such that what is left for white is right for black. So using Betza l and r modifiers would need a different description for white and black King. A new feature was added to the basic diagram script to handle this situation in a more convenient way: a new parameter 'castleFlip', when set to '1' in the diagram definition, will cause the meaning of left and right to be reversed when interpreting the XBetza description of castling for a black piece.

Because of the asymmetry of this variant it required some special attention to make sure the diagram would only allow each side to promote to its own pieces. What I did was define the promotion choice with an asterisk before each piece, meaning it can only come from the holdings. Then I stuffed the holdings initially with eight of each eligible piece type (enough to promote all Pawns to it).

Except for the Spartan King, which would only be a valid promotion choice if one of the Kings was captured. So I defined the holdings type such that it would accumulate captured pieces of the original owner. By starting without Kings in hand the Spartans then can only promote to King when one of their Kings is captured.

Castling

Only the Persians can castle, and this forced the Persian and Spartan Kings to be defined as different piece types. (If castling is specified with the aid of an O atom, the diagram assumes it is with a Rook or a corner piece of any type. And we do'nt want the Spartan Kings to castle with their Lieutenants!) This has the dubious effect of the Spartan Kings not being considered royal (as the diagram only considers one piece royal, by default the last one defined). So moves of Spartan Kings into check are not 'grayed out', like they are for the Persian King. But of course this is justifiable, as the Spartan King can actually expose itself to capture (if there still is a second one). So such moves can be legal. The diagram does not understand extinction royalty.

Move-power relaying

The Harpy relays Knight power to every friendly piece in its Q3 vision, and the Dervish relays limited Alfil / Dabbaba / Firzan power to any adjacent friend. It was a challenge to allow the diagram to do this, as how would one describe in Betza notation that, say, N moves are conditional, and what exactly that condition is? The solution I finally arrived at is to consider these relayed N moves as (multi-leg) moves of the Harpy, rather than simple moves of the piece that makes them. (To try that, drag a Dervish (the flag) to the promotion zone, and answer the promotion question above the board with 'Yes' to acquire a Harpy to move around. You can of course also try out the relaying power of the Dervish itself.)

So to make such a relayed move, one first clicks the Harpy (the 'activator' piece), and this highlights the simple moves of the Harpy (in green, as it is a non-capture-only piece), but it highlights all activated pieces in cyan, indicating that going there would just be the first leg of the move, and another leg may follow. Selecting a thus activated piece then shows the relayed N moves of that piece, and clicking one of those then moves the piece, rather than the Harpy.

That the first leg of a multi-leg move acts on friendly pieces to relay power, rather than on enemy pieces to capture them in passing, is indicated by an 'x' modifier for the first-leg modality in the Betza notation understood by the diagram. (This was one of the few characters not yet in use.) So the moves of the Knights in Knight-relay Chess would be written as mNxaN, where the xaN describes the relay of N moves to pieces an N jump away. For the Harpy it was a bit more complex, because the activation step (Q3) was different from the relayed move.

Locust capture

The diagram already did implement locust capture, also as a multi-leg move, where the possible locust victims are highlighted in cyan first. After selecting one, the final destination(s) get highlighted, so one can be picked to land on. In Scirocco the Zig and Zag pieces have Checker-like locust captures, where they have to land on an empty square. This move is indicated a cafmW or cafmF, the first leg (before the 'a') obligatory capturing, and the second leg in the same direction ('f') obligatory landing on an empty square.

Printable versions, a new general diagram feature

About the game

Based on studying the rules, the following characteristics struck me as imperfections, and are the reason that I did not rate it as 'excellent':

• There is an annoying asymmetry in the promotions of Alfil and Dabbaba. If Alfil promotes to Bishop then surely the Dabbaba should promote to Rook!? A Genie seems excessively strong: rifle capture is devastating. It would not be out of line as promoted Knight, however. The other 8-way leapers (Commoner and Camel) also promote to pieces much stronger than a Rook.
• Making the moves that could break severe color binding capture-only seems a bad idea, and makes the Stork a very awkward piece.
• That one can win by forcing repeats through perpetual checking is very unsatisfactory. Even Chu Shogi has always made an exception for that.
• The repetition rule prevents a losing side from halting progress of the future winner by checking, because sooner or later he would run out of new checks. But when the defender has a stong piece like Queen, this can basically take forever. Chu Shogi also suffers from that. A rule against roaming the board giving (ultimately) pointless checks is sorely needed.
• The Dervish seems to start in a wrong location for its move. To really help development I would like to position it in front of the Pawn rank, to give the Pawns behind it forward A and D steps. But due to its high-order color binding the Dervish can never get there. To enhance the Dervish, it would have been better to add some extra non-capture moves to it that would break the color binding (like mW), then to make it activate more moves in its neighbors (as was done in this revision).

The Lion Dog is now thought to have 3-step linear Lion powers, similar (but greater than) the 2-step linear Lion power of Horned Falcon and Soaring Eagle in Chu Shogi. That it should not have Lion power was argued in the TSA leaflet apparently on no other basis than that 3-step full (i.e. direction-changing) Lion power would make it much to strong, but the restriction to linear movement that voids this arguments was never considered.

It is now considered unlikely that promotion (on capture) was mandatory. Unlike Dai Dai Shogi, where most pieces do not promote (or start out promoted, if you want), having forced promotion in Maka Dai Dai would thoroughly wreck the game. Many of the strong pieces 'promote' to the weak Gold, (hook movers, Lion Dog), and there are no pieces in the initial setup that would promote to any of these lost pieces. So you would quickly end up in a situation with flocks of Golds, plus some rather uninteresting sliders. A much better rule would be that promotion is mandatory only when you capture a promoted piece, and optional when you capture an unpromoted one. That would preserve the interesting pieces much longer. The idea that you would 'inherit' the promoted property from you victim is in line with the following rule as well:

The strongest pieces of the game, Teaching King and Buddhist Spirit (compounds of Queen + Lion Dog and Queen + Lion) cannot be traded out of the game, by a rule different from the Lion-trading rules in Chu, but practically achieving the same: whenever you capture a TK or BS, the capturing piece promotes to that. (Using the just captured piece to replace it.)

This makes the game much more interesting than once thought. The major drawback remains the very large size, which makes it tedious to play. I designed a version of it about half the size, on a 13x13 board: "Macadamia Shogi", on which I posted a page here.

Note that I implemented the form of Superchess as it is played in the Dutch Open in Fairy-Max, and added support for it in WinBoard. People interested in playing Superchess against the computer, can download the entire package of WinBoard + Fairy-Max set up to play Superchess (although Capablanca, Cylinder, Berolina, Shatranj, Courier, the Unspeakable variant, Falcon Chess, and good old Mad Queen are also still on the menu) from:

http://home.hccnet.nl/h.g.muller/WinBoard_F.zip

The folder contains shortcuts for playing two kinds of Superchess, actually:

The kind that is played in the Dutch open has BN, RN, QN and KN compounds randomly replacing ordinary pieces in a symmetric array (two on Q-side, two on K-side) on an 8x8 board.

The other sub-variant features Emperors in stead of Kings as Royal pieces (an Emperor moves as King, but also has a two-step forward or backward (non-jumping) move), and has Betza's FWAD and WD, the Squirrel (NAD) and the BN compound as replacements in the initial array (also on 8x8).

This only samples a small part of the possibilities of Superchess, which features over 50 different fairy pieces, but it allows you to get a flavor of the game, at least.

I think this page does a very poor job in describing Falcon Chess compared to the compact description other CVs get on these pages. And this for addition of only a single new piece, for which the move rules could have been described (within the context of what can be supposed common background knowledge for visitors of these pages) with the in a single sentence:

'The Falcon is a lame (1,3)+(2,3) compound leaper, which follows any of the three shortest paths to its desination consisting of orthogonal and diagonal steps, which can be blocked on any square it has to pass over to reach its destination.'

That, plus possibly a diagram of the Falcon moves and a diagram of the array should have been sufficient. As it is now, I could not even find the rules for promotion amongst the landslide of superfluous description.

Note that my rating only applies to the page, not to the game. I haven't formed an opinion on that yet, it could be the greatest game in the World for all I know.

I have a question, though:

What exactly does the patent cover? As a layman in the field of law, I associate patents with material object which I cannot manufacture and sell without a license. Rules for a Chess variant are not objects, though. So which of the following actions would be considered infringements on the Falcon patent, if performed without licensing:

1) I play a game of Falcon Chess at home
2) I publish on the internet the PGN of a Falcon Chess game I played at home
3) I write a computer program that plays Falcon Chess, and let it play in my home
4) I publish on the internet the games this program played
5) I conduct a Falcon Chess tournament with this engine in various incarnations as participant, and make it available for life viewing on the internet
6) I post my Falcon-Chess capable engine for free download on my website
7) I post the source code of that engine for free download on my website
8) I sell the engine as an executable file
9) I sell a staunton-style piece set with 10 Pawns, orthodox Chess men, and two additional, bird-like pieces
10) I sell a set of small wooden statues, looking like owls, falcons, elephants and lions, plus some staunton-style pawns, plus a 10x8 board.
?????????

And more specifically: would it require a license to equip my engine Joker80 to play Falcon Chess (next to Janus, Capablanca and CRC) and post it on the internet for free download? If so, could such a license be granted, and what would be the conditions?