Comments/Ratings for a Single Item

@HG,

Hello,

I had just tried it and my advanced lyon defended by the DH got captured by the AI. I then tried it again. It seems to happend to player's lyon on 6th rank once the second dk pawn got moved. Maybe if you try reproducing such a position you may find the bug!...

The AI of the diagram now also has a vague notion of the Lion anti-trading rules. It isn't perfect yet, because it does not apply the rule for 'bridge capture' yet; you can just generally forbid capture of protected pieces of a certain type. It also doesn't limit it to distant captures, but I guess that only means it unjustly forbids moves that you would never want to make anyway.

Good job, Adam!...

Excellent, passed all my tests. Thanks again! I will be using this preset from now on.

You can find it here: https://www.chessvariants.com/play/pbm/play.php?game=Chu+Shogi&settings=chu

Would you share the link to your newest preset, Adam?

The preset has been posted, and everything seems to be working properly.

Everything should be in order apart from the restrictions against indirect trading of Lions (and the repetition rules, which i won't implement because it's way too complex). All I really did was copy the Tenjiku Shogi preset's code to this preset and modified the code to suit the needs of the Chu Shogi preset.

Just to make perfectly clear: any piece may capture a Lion, that has captured a Lion on the previous turn. Restrictions ONLY apply after a non-Lion captures a lion. This rule has been incorrectly written in some parts of this site, which I have complained about before. And thanks for working on a new preset, Adam ^^

I will test to make sure everything else is in order

In an engine I solve this by making a Lion that captured a Lion (from a distance, etc.)  a temporary absolute royal for one turn. Then playing Ln x protected Ln is considered exposing yourself to check. (In my Crazyhouse engine I do something similar to enforce the ban on castling through check: castling initially ends up with the Rook replaced by a second King. After move generation of the opponent (which would detect the King capture) I then replace that by the Rook it should be. After Other x Lion I make the opponent's Lion iron for one move.

All you need is the concept of 'temporary promotion', piece types that at the beginning of their own turn revert to the unpromoted form. And then have some extra types that are royal and iron.

Btw, note that the counter-strike rule on Lions does not hold when the two Lions are captured on the same square. If a Kirin captures a Lion and promotes in that same move (to Lion), it is allowed to recapture it.

A player may have 2 Lions as a Kirin may be promotted to a Lion

As I understand these, a lion may not capture a protected lion, and a piece may not capture a lion if one was captured on the previous move. While the second rule applies only to non-lions, it is applicable only in a situation in which a player no longer has a lion. So, that detail of the rule can be safely ignored, and it can be applied to any piece.

I am nearly finished making a Game Courier preset that enforces the rules of this game and displays legal moves. However, the Lion trading rules haven't been implemented yet because they are giving me some problems. Any ideas on how to solve this?

You can find the preset here: https://www.chessvariants.com/play/pbm/play.php?game=Chu+Shogi&settings=chu

No, those discussions are about the interactive diagrams.

Is there a new enforcing preset I'm unware of? 

When I try to promote a Dragon King, it promotes to a Tokin instead of a Soaring Eagle. However, this can be easily fixed by making the King the last piece and changing the parameters accordingly.

Ok, HG,  thanks!

Getting a Lion out early is OK; it is impervious to stepper attack by its igui capability, and can easily withdraw when chased by sliders because of its jumping ability. And if the opponent develops his Lion, you often have no other way to keep it at bay than opposing it with your own Lion.

But suppose your opponent will keep his sliders safely behind his Pawn wall, and advances his Copper, Silver and Leopard while you are dancing around with your sliders. No matter how fast you develop your sliders, they won't be able to breach the Pawn wall, as this is well protected by the opponent's sliders without him having to spend many moves: his sliders start there. At some point the Silvers and Coppers stream out through the occasional hole in the Pawn wall, and will start forking your valuable sliders, which are trapped in the narrow area between the Pawn walls (usually both sides advance all their Pawns one step without opening up large holes, to allow the Side Movers to cover the original Pawn rank). You will get slaughtered.

Sliders are very valuable in Chu Shogi, because they promote easily in the end-game. Promoting steppers, OTOH is very difficult: they need to approach from afar, and by the time they reach the zone the opponent will oppose them with his steppers, needing far fewer moves to do that. And you have to overcome the extra defense provided by his Side Movers; you cannot neutralize those with your own Side Movers. Basically you can only promote steppers that are left over when all stepper material of the opponent has been traded away. So if there is an imbalance where you have steppers, and the opponent tactically equivalent sliders, and the potential promotion gain is the same, you are toast: he will promote all his sliders long before you promote your first stepper, and this will put you at such a tactical disadvantage that you will not have any steppers left by the time the opponent has not enough material left to prevent them from entering the zone.

In warfare one should never expose one's artillery to infantry attack!

About the strategy part of the article.

From the games I had played against user Dax00 it seems to me the advices here are not optimal although wikipedia states roughly the same things regarding the early moving up of steppers.

In our games dax00 has taught me to early lyon jump in front very early (the latest at turn 3) and then the stronger pieces take relevant forward positions until it becomes worthless for them to keep dancing around, and only then steppers (and maybe phoenix) kick in slowly but surely as the strong pieces are stuck in their duties :)!

What am I missing?

I have not really looked at those problems to see if I could find an easy flaw since I first analyzed them, and have been busy with other projects since.It seems a daunting task to figure out if the lack of a solution is due to a plausible oversight of the composer, and what he overlooked. I am not even sure how one would have to approach that problem. The computer just concludes whether there is a mate or not. It doesn't know the concept of 'nearly mate'. Because all the moves are checks it is not uncommon in problems that do have a solution that there is only a single legal move for gote in some positions, or only a single move that does not get him mated very quickly. So having only a single move to escape the mate in some variation doesn't really indicate the composer must have overlooked that move. (Ignoring the problem that the computer usually does not know there is only one refutation to the mate attempt, as it doesn't search any alternative moves once it finds the refutation. This could be solved by altering the program to require at least two refutations in each position, at the expense of driving the solution time up by a factor of 2^N for a mate in N full moves.)

It really requires human judgement to identify a move as a plausible candidate for being overlooked.

Perhaps the following would work: equip the program with a 'conditional exclude-move' option, through which you could tell it: in this position, you must consider that particular move as illegal. You could then start running the engine on the the flawed problem; it will find a principal variation that keeps up the checking as long as possible, but eventually it will run out of checks. You can then try to 'repair' the problem by 'outlawing' the gote moves in this PV one by one, starting at the end, and try to solve the problem for that case. If the outlawed move was the only move that escaped mate, the problem would then have a solotion, and the defensive move could have been the one overlooked by the composer. If the problem is still flawed, because gote has an alternative escape, we probably are already in a position that was never intended to occur.

@Dr Muller: You had mentioned that you had analyzed the D document of historic chu shogi problems in MSM, had reserved the results of your analysis, and had concluded that 18 were proven flawed.  I wonder if you had reached a conclusion about the 18 like one that Mr Hodges proposed about the D document generally, that necessary pieces possibly had been omitted or erroneous pieces introduced into the diagram to act as a security device against plagiarism.  I read your suggested corrections to problems in the other 3 collections; I do not ask you to divulge more than you want about D, only to ask if your research suggested that the flawed problems might be fixed by the removal, change, or addition of pieces to the diagram.  Kind regards!

Only Pawn, Leopard and promoted Leopard cannot not force checkmate on a bare King. Many of the weak pieces lack mating potential, but against a bare King they should be easy to promote, and all promoted types except Bishop have mating potential. Because they virtually all have at least one orthogonal sliding move, and can move perpendicularly to that. That is all that is required, and makes the mate in fact quite easy (so that last century even a mechanical machine was built to do it!). The other exceptions are +P and +DE. As it turns out, Gold has no mating potential on 12x12 (it stops at 11x11), but DE and +DE still have (up to 14x14, IIRC, which would affect Dai Shogi). A Blind Tiger that cannot seek shelter with its King can sometimes be chased by the bare King to its back-rank, and get lost there. And Pawns approached from the front are doomed too, if the bare King gets there before yours.

The only pair of pieces without mating potential is a pair of +FL on the same 'square shade'. Provided none of them is trapped, which for two Pawns far away from each other can be a problem.

Dr Muller, you mention the bare king rule as used by the Nihon Chu Shogi Renmei, but I have to wonder if your computer analysis has revealed what pieces singly or in combination are sufficient to force or at least deliver checkmate on a bare king in chu shogi.

These are mere presets that do not include settings files. I edited the HTML forms for the Chu Shogi presets to use FEN code that has not been URL encoded.