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Note that I adopted the rule interpretation here concerning the possibility of jump-capturing generals to jump-capture (as opposed to jump over) each other that is different from what the opening theory of Colin Adams assumed. And that this completely invalidates all of Colin's opening theory, which completely revolved around using the first-move advantage to make a quick attack on a boxed-in Fire Demon over the head of a lower-ranked jumping general. In the rule interpretation described here all such attacks are immediate suicide, as the lower-ranked general would simply capture any higher-ranked general that could jump over it. <p> I hope to be able to put a fair amount of work into HaChu this year, finishing its Tenjiku play, as well as (Maka) Dai Dai (or at least my reduced-size versions of these).

In the Betza description of the lance below where the "First rank" subtitle is written there seems to be an error. I'm quite sure that the lance should be fR but there it says just rook.

How is the fire demon's burn effect taken into consideration by the Betza notation :)?

Thanks for spotting the error. Betza notation was originally designed for indicating moves; (i.e. where a piece can end up relative to its current location), and not for specifying side effects. I admit that the XBetza extension breaks that rule by introducing the 'e' modifier for indicating e.p. capture. And the 'a' modifier for describing what are basically multiple moves per turn can in theory be used to describe side-effect captures, by having the piece jump around before it finally settles on its destination, trampling everything that should disappear first. In the case of the Fire Demon this could be done by having it encircle its final destination with steps that have mpc mode, except that this would make the capture optional, as the 'p' part allows you to jump over the opponent as well. In XBoard I solved this by an ad-hoc extension: 't' in a non-final leg ('tame') there limits any hopping to friendly pieces only. (In final legs I use it to specify a move cannot capture royalty.) So the mode mtpc would do it, and make the Fire Demon's move something like

gyafmtpcabrmtpcafmtpcarmtpcafmtpcarmtpcafmtpcarmtpcarB

and similar things for the vR and aaK components. (The 'gy' in the first leg changes the range from slider to leaper for the subsequent leg(s).) This does not seem really helpful as explanation, however, and the 'a' operator was never meant to be abused for this purpose. (And note that the interactive diagram currently cannot handle more than a single side-effect capture.) It would also not work at the edge of the board, because the FD would not be able to complete the detour there without falling off. This could again be solved by assigning a new meaning for the modifier 'o' in non-final legs, for legs that can step off the board. All intermediate legs should then have the mode mtpooc.

To be of any practical use, a notation would have to be far simpler. I have been playing with the idea to introduce a modifier for 'explosion', (say 'xx') indicating mandatory removal of all adjacent enemy pieces in combination with the mentioned ordinary modes. That would give move components like xxmcB for the FD, which is a lot clearer, and more in line with the philosophy of Betza notation. (I already used a single 'x' for another purpose in the diagram, namely move relay.) Captures of Atomic Chess could then be xxmcdN, etc., the extra 'd' (''destroy') indicating it also works for friendly pieces.

The problem is that this still doesn't give a complete description of the Tenjiku Shogi Fire Demon, as the latter also has passive burning ability, during the opponent's turn, which actually dominates the active ability. So the burning is actually more like a special game rule than a move description; every turn ends with removing your own pieces adjacent to an enemy Demon, and after that removing the enemy pieces adjacent to your own Demons, irrespective of whether the Demons moved or not. That would decouple the burning from the move.

 

Whoever said life is simple got it wrong :)!

I made an attempt to implement Tenjiku Shogi in Jocly. I even spent some time on the evaluation function. As a result it actually seems to play a reasonable game at 30 sec/move, despite its low search depth. (Jocly's generic JavaScript AI is not very fast.) The web applet can be found at:

http://hgm.nubati.net/jocly/jocly-master/examples/browser/control.html?game=tenjiku-chess

In 2D mode most pictures are not shown properly, but I'm not sure you've got there!...

Same in chu shogi!...

Hope I don't trouble you too much HG!...

Ah yes, I only payed attention to the 3d display. Yet the 2d display is always important, as the images for that are also used in 3d for the promotion popup, which asks you whether you want to promoe or defer.

When I have more time I will make a file with images of all Shogi pieces.

To me the trouble is that the 2d display is more feasable. The 3d one consumes a lot of resources.

Also I don't reconnize all the required kanji!

Yeah, the Jocly 3d graphics run quite slow when you don't have a GPU (as is apparently the case on the virtual machine where I run Linux). I was a bit in a hurry to at least get the AI working, because I had entered it in the yearly Modern Tenjiku correspondence championship, and its clock was already running, and had ticked away 96 of the available 120 days. So I didn't pay any attention to non-essential details, as I normally would.

BTW, 2d would not solve the kanji problem...

In the link you had posed, 2d was not kanji. And even if it were, I'd at least be able to memorise pieces easier.

I see your point about priorities HG. I was not picking on you. Good job. I was only pointing it out!

I managed to make rule-enforcing preset for this game. It enforces almost every rule in this article, from the piece moves down to the Fire Demon's burns. The only rule I could not implement was the rule regarding repeated board positions since it is very complex. So it is up to the players to abide by these.

You can find it here: https://www.chessvariants.com/play/pbm/play.php?game%3DTenjiku+Shogi%26settings%3Dtenjiku

That is impressive Adam , thank you!

One question. Let's say a Lion, Horned Falcon, or Soaring Eagle skips a turn inside its promotion zone (They are the only promotable pieces with this ability). Would that piece be allowed to promote after doing this?

In my rule-enforcing preset for this game, promoting a piece after it skips a turn is currently disallowed. This is because the preset is based on my rule-enforcing preset for Suzumu Shogi (a game which explicitly prohibits promoting after skipping a turn). However, historical sources (which are already terse and/or incomplete) do not elaborate on this particular situation as far as I know. Should I remove the code disallowing promotion after skipping a turn?

Historic rule descriptions are quite minimal, and in particular do not waste words on purely hypothetical matters. Turn passing is one such thing, as you never would want to do it in the first place. There also can never be a reason to not promote a Lion, so an unpromoted Lion in the zone that wants to pass a turn would be a double rarity. For Falcons and Eagles this is a different matter, as they might actually be more valuable than the BG and RG they promote to. (It seems these promotions were assigned mainly as leftovers.) Especially in a late end-game, when there is almost nothing on the board you could jump over. No way I would want to convert my Eagle to a Rook General when so few pieces are left that I could be in zugzwang...

Promotion rule is such that you can only promote on a noncapture when you enter the zone. It seems to me a turn-pass should count as a non-capture. So if you are already in the zone, definitely no promotion.

A more interesting question is whether they could promote when they are just outside the zone, and capture a piece in it through igui. Since promotion is at the end of a turn, I would say that after a turn pass you did not enter it. If you see it as a double move, the first move would enter it, but would not allow you to promote because it is not the end of your turn. The second move would not allow you to promote because it did not enter the zone and doesn't capture anything.

I completely forgot that the promotion rule was different. I'll get to fixing that right away.

The rule-enforcing preset now properly enforces promotion rules.

I tested out some promotion scenarios to see if the rules are enforced correctly. Everything seems to be in order, except for one case.

A lion enters the promotion zone on a non-capture, then exits the zone while capturing a piece. A promotion option should be visible.

I am not sure that is the case. And the way I described the rules it would not be. It starts and ends its move outside the zone, and that did not fit my idea of "entering the zone". But I admit that historic rules give no clue about this.

As a historic game based off of chu shogi, tenjiku shogi rule philosophy should by default defer to chu shogi rule philosophy. Taking the legality after each step, we only need to consider the final step for any multiple-step mover when evaluating whether it can promote. And since capturing a piece while leaving the promotion zone is a perfectly valid way to promote, this should be clearly allowed.

Edit: Now that I've thought about it a bit more, you should not be able to promote if: an unpromoted piece begins in the promotion zone, captures a piece in the promotion zone on its first step, then on its second step makes a non-capture.

I definitely agree that unmentioned rules should be understood to be the same as in Chu Shogi. That lion-power moves should be broken up in two steps in Chu is not so obvious, though. In fact I have strong disagreement about that with the Chu-Shogi renmei, in connection with the Lion-trading rules. The disputed case is when you make a double-capture on Pawn + Lion, where the Lion was standing in front of the Pawn. My interpretation of 'protected' is that recapture should be possible. The historic rule descriptions, by mentioning the case of a 'hidden protector', tell us that you have to judge the situation after the move, not before. The whole idea of those rules, after all, is to prevent Lion trading, and when there is no recapture, there can be no trading. The Chu-Shogi renmei, however, claims that my interpretation implies that the move is made in two parts, and that only after the first, which takes the Pawn, the Lion has become unprotected. And they insist that protection must be measured before the move, and has nothing to do with recapture. And then they continue by saying that you cannot split the move in parts and consider those as independent moves, so that the doomed Pawn would count as a protector.

Also note that 'igui' seems to mean 'stationary eating', and 'stationary' usually means you don't move at all. So one could argue that the underlying philosophy that led to that name is that the Lion never visits the zone when it takes a piece in it through igui.

I strongly dislike how the chu shogi renmei has approached a variety of things, and their incompetent leadership. The old texts clearly state that a lion moves two times one step (not one time two steps), and then assesses the move after each step. The JCSA also uses that ridiculous lance promotion rule.

The term is "sole protector", and yes, I am agreed that what should be assessed is whether a recapture is possible. 

To say a lion does not move for igui is laughable. The terminology arises from the possibility of taking a piece and returning, not some single extra ability to take a piece at distance, like a shooter. Since igui is a common 2-step hit-and-run tactic, there is a special name for it. Nothing more.

Anyways, my points about the promotions in tenjiku shogi logically follow, and it appears you have no objection at the heart of it.