Mighty-Lion Chess

I designed a new 'modest' Chess variant, which adds a single new piece to orthodox Chess. This piece, called 'Lion', is the dominant piece of Chu Shogi. It is an extremely interesting piece, and I felt said that it could only be enjoyed in Chu Shogi, with its horrendous complexity of 36 piece types. Hence I came up with this variant.

The Lion moves as a King, but then twice per turn! It can change direction between steps, and the first step can be taken as a jump, if you so please, so the Lion cannot be blocked. The second step is optional, so it can also move as a normal King. The interesting thing is that a Lion can still make its second step if the first step was a capture, so it can capture upto two pieces per turn. It is also capable of 'hit-and-run' capture, withdrawing to a safe square (possibly the square it came from) after the capture, leaving any protectors of its victim staring at thin air.

This makes a Lion a very powerful piece. It is true that it does not have all the moves of a QN compound (the 'Amazon'), but its double-capture abilities make it way stronger in practice. (About 15, where Q=9 and A=12.)

In variants of this type, there always is the danger that the 'exo-piece' is quickly traded, leaving a game of normal Chess with a wrecked opening. To prevent that, there are rules that forbid such trades (also borrowed from Chu Shogi): A Lion is not allowed to capture another Lion from a distance when pseudo-legal recapture of it is possible. (Another way of saying this is that the Lion that made such a capture temporarily becomes a King during the opponent's following half-move.) Capturing an adjacent Lion with a Lion is always allowed (as normally you would use hit-and-run anyway). Indirect trading is also forbidden: after your Lion is captured by a non-Lion, the opponent's Lion may not be captured on the next half-move. (It becomes 'iron'.)

These rules guarantee the Lions will typically remain in play for most of the game, despite the fact that they are so powerful they will be 'banging heads' very quickly. (Subjecting Queens to similar rules in orthodox Chess would also be an interesting experiment!)

Pawns promote as in FIDE, i.e. they cannot promote to Lion. The initial setup I envisaged was this:

This leaves the strongest pieces on the board (to provide some counterweight to the Lions, which otherwise would become all-powerful). Over the board the game could be played by wrapping a rubber band around one of the Knights, or set in on a checkers chip pedestal, to turn it into a Lion. An alternative setup keeps both Knights on the board, and just adds the Lion as a 17th piece. (You could use the bare checkers chip, or an inverted Rook of another set as Lion.)

(Which setup would you think best?)

Both setups seem pretty good, I'll have to try them both out. I do have one question about the trading lions rules.

It's not legal to trade lions, but you can "hang" your own lion by mistake? Is that correct?

As far as the setup goes, replacing the knight looks more elegant, but both seem like good setups. I would suggest a possible third starting position as well, same as the first except the knight goes on a3 and pawn on a2. All 3 I think have advantages/disadvantages.

Indeed, if you hang your Lion it can be taken even from a distance by the other Lion. There actually is a slight extra complication (also taken from Chu Shogi): if you capture a Lion from a distance through another valuable piece (=non-Pawn) this would be allowed even if the Lion would be protected. The intermediate piece acts as a bridge, as it were, making it no longer a capture from a distance. Normally it would of course never be attractive to allow this, as one side would lose a piece plus a Lion, whie the recapture only gains him a Lion. (And the bridging piece could usually be captured hit-and-run fashion anyway, even without trading Lions.)

I implemented this game in the WinBoard and XBoard development version (to be eventually released as version 4.8.0). I finally decided to take the setup that simply replaced the Knight. I have no engine for it yet, though. I did some experiments to verify that the Lion would not be too dominant, by making my Chu Shogi engine play a slightly modified version of it, which has no castling and e.p. capture. (Being a Shogi engine, it did not support those moves.)

It's far too OP; this starting position is around equal if white moves 2 times a move. The king then moves just like the lion, and a single mistake can easily end in checkmate. The other pieces would be worth much less. The beauty of chess is that all the pieces can dominate each other. Pawns can dominate queens (rarely, but happens once in a while), knights can dominate rooks and so on. No piece can ever dominate a lion.

I thought of a strange situation.

White hangs his lion, black doesn't see. Black also hangs his lion. White captures black lion with rook. Black sees he can also take white lion with rook, but actually he cannot because of the "iron" lion power, correct? Even if the rook would be safe after the capture. Makes sense I guess (be careful with the lion, but don't overetend yourself to take away your opponent's).

Indeed, you would not be allowed to 'counterstrike' against his Lion immediately after yours was taken. If you could give an intermediate check, however, he would have to evade it, and you could take his Lion the next move. It would not matter if the black Rook in your example could be recaptured. (It is funny that you mention this, however: the Lion-exchange rules I describe are the historic rules for Chu Shogi, which has been around since ~1250 a.d., and those would unconditionally forbid the counterstrike. But the present-day Japanese Chu-Shogi association has adopted the so-called Okisaki rule, which says that the black Rook would be allowed to capture if it could not be recaptured.)

To not make the game too drawish, I thought of the following refinement: In the rule that you are not allowed to play L x L if the latter is protected, protection by King should not be counted. This would make Lion trading possible once you have no other pieces left than King + Lion, and thus provide a way to win KLPKL, which otherwise would be a dead draw. In the middle game this would have little effect, as it would be sort of suicidal to count on your King as the only protector of your Lion.

Lions have their weaknesses too. Because it is a short-range pieces, it can easily be trapped. Controlling two neighboring ranks with Rooks confines a Lion in the same way a single Rook confines a King. In K+L vs K+Q+R the Lion is toast. I am not even sure K+2R vs K+L cannot be won on 8x8. (In Chu Shogi, on 12x12, it would be an easy win, as you would just drive the King to the edge mate with 'hand-over-hand' checking, and the Lion can't do much more than watch idly.)

Like the Amazon, the lion also controls all squares in a 5x5 square(with it being in the centre)! Awesome!

" (About 15, where Q=9 and A=12.)"

I searched up chu shoji on Wikipedia and it said the approximate value is about 20 (although this might not be true)

You have to be careful, because (Chu) Shogi Pawns are not the same as FIDE Pawns. Indeed my Chu-Shogi engine HaChu uses L=100, Q=60, P=4, so there a Lion would even be worth 25 Chu-Shogi Pawns.

I want a Chu Shogi set now, but I only know 1-3 people who would ever play that sort of thing, and I bet they wouldn't play it more than a few times.

HGMuller, what do you suggest? Can Xboard play Chu Shogi? If not whats the best way to play?

Also, the kanji sets are obviously cooler, but I think one of the westernized sets might be better to start. I like the sets that just use picture of what the piece is suposed to be (I.E. Drunk Elephant would be an elephant head instead of an abstract representation of how it moves). That way you still have to learn the pieces and how they move, but I can take my time learning 20-somethin kanji symbols.

Actually I just implemented it in XBoard, using pictographical piece representation. (Before that only the WinBoard Alien Edition supported it, with mnemonic pieces.) I did not always use the image corresponding to the Japanese names, however, as I wanted to use as many pictograms as I already had, (so the Horned Falcon became a Unicorn), and some names are hard to depict. (So the Vertical Mover became a Sword pointing up.) The initial setup looks like this:

The user can supply his own piece images in XBoard (preferably SVG, but you can also use PNG if you don't mind it getting a bit smeared on scaling). The HaChu package inclucdes a set of 'kanji pieces' (more like bare kanji, actually).

Both the XBoard and HaChu sources can be downloaded from my on-line source repository:

http://hgm.nubati.net/cgi-bin/gitweb.cgi

(XBoard: 'master' branch, HaChu: 'public' branch, for both download latest snapshot.)

For compact explanation of the rules, see my rules page http://hgm.nubati.net/rules/Chu.html .

Chu Shogi can be played on-line against human opponents (live, not turn based!) on http://81dojo.com (Jupiter server. Not very busy, though. And the interface only has kanji pieces.)

Way too OP. End of descussion.

A protected lion can trap an unprotected lion on the edge of the board if no protection can be found for the latter.

Indeed. This is actually a common beginner's mistake in Chu Shogi, to go on a plunder raid with your Lion for annihilating one of the opponent's wings, only to discover that you cannot get out after he withdraws his Lion to cut you off. Your Lion is than trapped in a corner, and will eventually be attacked without the possibility to protect or trade it.

If we would combine the lion with the Superchess joker, we would have to decide about the rules against trading lions. Could a Joker that temporarily moves as lion take a protected lion?

I would say 'yes', for several reasons. Jokers in Superchess take over the move of the previously moved non-Joker, none of the other properties. E.g. if a Joker must move as a King, you can move it in check.

But more importantly, the rule is there to prevent Lions are traded. If you capture a protected Lion with a Joker mimicking a Lion, and get recaptured, the Lions were not traded, but you gained a Lion for a Joker. No reason to outlaw that.