Ratings & Comments

This looks good.

The Centurions are an interesting idea. The 1d shogis have tried this kind of idea before with a single forward-only King.

If it turns out there are too many Centurions, you can always reduce the number of Centurions to two. However, the winning King promotion likely takes care of that, at least if it is an immediate win.

Now that you say that, it clears up all the previous confusion. I guess my autism got in the way.

I can see the way you interpret "non-lion" in the counter-strike rule becoming a point of contention though.

I cannot see that, and never have spoken to anyone who thinks that. (Which includes the Chu-Shogi Renmei, the 81-Dojo community, the German Chu-Shogi Association, the TSA, Hidetchi, the Wikipedia maintainers...) If it would have said "A Lion cannot capture a protected Lion"... Would that also mean that a Rook cannot capture an adjacent protected Lion, because 'Lion' refers to 'Lion move', as it did not explicitly contain the word 'piece'? And if 'Lion' by default refers to a piece, why would 'non-Lion' be different?

I read in LiChess 'issues' (in particular about Ln x P x Ln without recapture possibility) that the developers want to follow CSRM rules, even though most people consider some of the deviations from historic rules there non-sensical. And the CSRM definitely considers 'Lion' a piece type, and not a move.

[Edit] In the I.D. the AI does this correctly. But the problem is caused by the way the latest user move is passed to the AI. This derives the move from the origin and destination highlights, so it completely misses any locust capture.

I did test the position I gave you by having the AI capture the Lions instead of the user, but this too seems to not properly invoke the counter-strike rule, though I suppose you still have to update the source file. I'm guessing the problem is that the way the AI gets the last move in general is through the origin and destination squares.

I can see the way you interpret "non-lion" in the counter-strike rule becoming a point of contention. The rule does not explicitly say "non-Lion piece" when it says "a non-Lion cannot capture a Lion...", which is the source of this confusion.

but apparently thinks non-lion refers to non-Lion moves though, rather than non-Lion pieces, ...

I am not even sure what that would mean. Of course the consensus is that non-Lion refers to a piece type, and until now I have never seen any other interpretation. The 81-Dojo server (when it was still featuring Chu Shogi) interpreted it as types. No phrase that would not explicitly contain the word 'move' or 'capture' would ever refer to a move. Do there really exist people that seriously would want to argue that when the rules specify "the Queen is not not allowed to capture Pawn" that this means Rooks, Bishops, Kings and other Pawns are not allowed to capture a Pawn either, because they would do it through a Queen move? This is insane.

The author, H. G. Muller, has updated this page.

If you make the same moves in Jocly, the same thing will happen, just so you know.

One of the LiShogi developers responded to my bug notificaton, but apparently thinks non-lion refers to non-Lion moves though, rather than non-Lion pieces, which leaves me wondering what the general consensus is. I would assume it to be piece types, based on the explanation of the another square clause.

Indeed, it seems that locust capture of the Lion does not set the 'iron lion' flag. Counterstrike through locust capture is forbidden, though.

Good catch!

[Edit] In the I.D. the AI does this correctly. But the problem is caused by the way the latest user move is passed to the AI. This derives the move from the origin and destination highlights, so it completely misses any locust capture.

Indeed, it implements the counter-strike rule for single captures. However, the Soaring Eagle and Horned Falcon can move again after stepping in certain directions.

Upon further testing, it seems that the counter-strike rule is not being invoked when a Lion is captured and then the capturer moves away. For example, in this game in the I.D., after promoting the Dragons on h9 and e4, if Black's Soaring Eagle captures White's Lion and then moves to another square afterward, the counter-strike rule will not be invoked and the AI will capture Black's Lion with White's Phoenix.

1. h5 e8 2. Qh4 Qe9 3. Qe7 Qh6 4. Qxe8 Qxh5 5. Qxf9 Qxg4 6. Dd2 Di11 7. Ti2 Td11 8. Oh2 Oe11 9. Tf2 Tg11 10. e5 h8 11. Xe4 Xh9 12. Xg6 Xf7 13. Xxi8 Xxd5 14. Qf5 Qg8 15. Dxh8 Dxe5

The moves you need to make manually are:

16. Dh9+ De4+ 17. +Dxg10xh9

If you make the same moves in Jocly, the same thing will happen.

The same thing happens in LiShogi, since the same behavior is taking place. I have already notified them about what I have found. One of the developers apparently thinks non-lion refers to non-Lion moves though, rather than non-Lion pieces.

Indeed, the counterstrike should be forbidden here.

The Interactive Diagram does implement the counterstrike rule: when you place both Lions in front of an enemy GB, switch on the AI, and play GBxLn, it will not capture the Lion. In the highlighting you won't see it, though, as the I.D. does pseudo-legal highlighting. Moves that expose you to check will also be highlighted. (If it is the King making such moves these are highlighted in grey, but betzaNew.js doesn't even do that anymore. Perhaps one of these days I will subject the highlighted moves to a legality test, and use another highlight symbol for the illegal ones.)

The same test appears to work in Jocly, though. And then it doesn't even highlight the counterstrike GBxLn.

Question. In the position below (from LiShogi), Black has just captured White's Lion. The recapture of Black's Lion via White's Soaring Eagle via a Lion move, which is allowed in LiShogi, clearly violates Chu's counter-strike rule, right?

If this is true, then both the Interactive Diagram and the Jocly implementation overlook this restriction when a Lion is captured on the first step of a multi-move.

The GC preset enforces the rule in such situations, but this is not reflected in its display of legal moves.

P.S. I have already notified LiShogi of this via Discord.

The fairychess-style code I was going for was giving me serious grief, so I decided to instead try to implement the Lion-trading rule display in this preset instead. No luck so far, though its plausible I am just being an idiot. For now, I will leave this preset as the default one, and leave it in its current state, which I know works properly. It might not be ideal, but it is good enough. Sometimes I get so wrapped up in whether I could, that I don't stop to think whether I should.

(Uses Shatranj version, K+G vs. K is mentioned in historical sources)

Note that the historical sources only mention that K + promoted Gold (= Rook) vs K is a win.

The HaChu engine allows Ln x P x Ln if no recapture is possible, which I am convinced is the historic rule. Historic sources give an example that makes it clear the situation after the capture that should be decisive ('hidden protector').

Since there are some discrepancies between the current GC preset and the rules that most people have reached a consensus on (mainly having to do with the anti-Lion-trading rules), I will make a new preset that patches them up, and uses sets with larger graphics to make it more user-friendly (specifically, my large Mnemonic pieces, Eric Silverman's 1-kanji pieces, and Bob Greenwade's pictogram pieces, using the XBoard/Interactive Diagram IDs). I also plan on making the preset correctly exclude moves that violate the Lion trading rules when highlighting legal moves.

This new preset will be based on the fairychess codebase and its Chu Seireigi version, and the multi-move code I have in place for the current preset at the time of writing.

Changes coming in new Chu preset (TLDR):

• New graphics sets used (my large Mnemonic piece set, Eric Silverman's 1-Kanji set, and Bob Greenwade Pictogram set)
  • Uses XBoard/Interactive Diagram IDs
• Correct exclusion of moves that violate the anti-Lion-trading rules
• Possibly options for certain game situations
  • First Lion step after final destination: true or false
  • King Baring (uses Shatranj version of the rules for simplicity): true or false

When I first saw this game, I didn't think much of it, since I was more focused on larger Shogi variants, especially Tenjiku Shogi. However, now I have a few games against Jocly under my belt, and wow, this game completely blew me away. It is an absolute joy to play, despite its size and complexity (which melts away after a couple games). However, it is not completely flawless.

Some rules, such as the King Baring rule (Uses Shatranj version, K+G vs. K is mentioned in historical sources) and repetition rules (borrowed from Xiangqi) that are currently played by are modern contaminations from other games and/or are warped versions of things mentioned in the historical documents, but I am willing to include these two rules, as they help with decisiveness without being redundant or overly complicated.

However, I am not willing to play by the "Okazaki" rule, and I would never recommend using it, which allows recapture of a Lion after another Lion has just been captured, if said Lion is unprotected. There is no evidence that it was a part of the historical game, and it kind of defeats the purpose of the rule against indirect Lion trading, so why did someone think it would be a good idea to have this? All it does is add confusion and increases the chance of a simplified game, detracting from the playerr experience.

It is also not clear whether a Lion taking a Pawn/Go Between and then a Lion is allowed if the enemy Lion is undefended after taking the Pawn. Both sides have evidence arguing for them (the hidden protector example for yes, a tsumeshogi in Dr. Eric Silverman's Chu Shogi Part II article, explained in the An interesting quirk in the Lion-trading rules section, for no). Personally, I prefer that is is allowed, since no recapture is possible after the move, and there is no specific mention of this situation in the historic rules.

However, despite these problems, Chu Shogi is still easily among the best games of its kind. If you like Chess variants, you should give it a try.

Addendum - An attempt at a drops-playable Chu Shogi variant

Chu Seireigi is an attempt to combine elements of Chu Shogi with the ruleset of modern Shogi. It also has the benefit of not needing any special rules to preserve its quality, fixing all the problems with the modern "innovations" for Chu Shogi that I mentioned above. Players are disincentivized from trading off the most powerful pieces in many cases because they would just go into the player's hands, making them even more dangerous. The repetition rule is simply that of Shogi (draw, except perpetual check loses), and the drops make King-baring extremely rare. However, this comes with the unfortunate downside of having to remove all the multi-move abilities from the game, as otherwise the balancing would be thrown off.

I'd like to try this if you could add it to game courier