Ratings & Comments

I find nightriders difficult to visualize, even with the three-colored board, but despite that they seem to work well in the grand apothecary games since there are enough pawns and weaker pieces to block them.

In my opinion riders based on a leap other than a king step are very awkward to play with. That holds for NN, but also DD and AA. It is never intuitively clear whether the path between such a rider and a distant target is blocked, especially when the blocker is far from both. For me that makes them annoying pieces.

I guess the problems with tactically non-quiet opening positions can be avoided by putting all pieces more valuable than a Nightrider two ranks behind the Pawns. Then the Pawns will block any Nightrider attacks on them. And of course make sure all Pawns and pieces directly behind them start protected.

In my three games described below I have nightriders and even their compounds the unicorn and the varan.

https://www.chessvariants.com/rules/grand-apothecary-chess-alert

https://www.chessvariants.com/rules/grand-apothecary-chess-classic

https://www.chessvariants.com/rules/grand-apothecary-chess-modern

I have previously observed that games with nightriders are hard to design as their long jumpy forks are very difficult to stop. I remember seeing people over here thinking also along these lines but I can't remember who. I'm sorry.

For this exact reason I though that the nightriders are game breaking in my 3 games mentioned above. I have put them there because I have though them to be natural fairy pieces to be used. When first confronted with the final versions of the games I have feared that the black heavy pieces will be easily forked by white and in doing so creating an unhealthy advantage for black.

But last night I have played a few openings, in each of the games, by myself intentionally testing for this. I seems black can always defend somehow, by blocking or running, and then counter by attacking the advanced nightriders and gaining tempi on them. The games are thick enough so that early on nightriders are not such troublemakers anymore. Careful maneuvering of the nightriders should still be an important late opening- middlegame theme, but it does not seem to be that dangerously unfair then.

What do you guys think about games with nightriders in general?

There's something a bit strange about the sandbox, and I'm not really understanding how it works. I wanted to try my hand at making a knight that takes 2 steps and bends 45° right after each move (sort of like a right-chiral Rose), and eventually what I ended up with is hlalfNhrarfN.

In other words, it's a knight that can either take a left-chiral step and bend to the left (???) or take a right-chiral step and bend to the right. Why do I have to specify that it continues left-forward? If you just look at hlalfN it behaves similarly to a rook that can only take 4 steps. But if it just took a left-chiral step and bends further to the left to take its next step, how does it end up back on the same rank or file that it started?

I can't make sense of why it works, or should work, like this. It seems arbitrary. A left-chiral version of this would look like hlarfNhralfN... so to specify a left-chiral one I need to go against the previous chirality and to specify a right-chiral one I need to use the same chirality?! There is no innate property of "right" and "left" that makes them unambiguously correspond to "same-chiral" and "opposite-chiral", so why is it implemented this way?

Same to me.

For me, too!

@ Fergus:

This CVP site has been painfully slow (for me anyway) for at least a couple of weeks, especially when trying to move on GC. Any idea what's happening?

It strikes me as a bit inconsistent that an Ichor compulsion would not count as resolved when you push the piece onto other Ichor, while it would count as twice resolved when you push it onto a Ghast square, and then back onto the same Ichor. Of course there is a clear precedent in that you don't have to completely resolve Ghast compulsion in a single move, but there at least the severity must decrease. It would be more consistent to require all types of compulsions on the same piece to be lessened. (Which for Ichor and crowdedness would mean these have to entirely disappear.)

But perhaps this is completely moot, because players would try to avoid compelling their own pieces very strongly, even when it is not required by the rules. Still, requiring more thorough resolution of compulsion would make it easier to checkmate. I don't know if that is good or bad, though.

It's clear that the rules of compulsion as laid out here are not quite formal. I took my own stab at interpreting them on the itch.io page that I linked. To summarize my interpretation:

• Every compulsion defines conditions under which it is satisfied.
• Multiple occupancy compulsion is satisfied by moving off or destroying the piece entirely (plus some edge cases).
• Ichor compulsion is satisfied by moving off, being pushed to a non-ichorous square, or destroying the piece entirely (plus some edge cases).
• Ghast compulsion is satisfied by fleeing, being pushed further from the Ghast, destroying the Ghast, or destroying the piece (plus some edge cases).
• If it's your turn and one of your pieces is compelled, you must make a legal move that satisfies at least one of your pieces' compulsions.
• There is nothing wrong with adding new compulsions to your pieces, although this is only possible with either a Go Away's push or by a Wounded Fiend leaving a square containing another one of your pieces.

While typing this up I realized that there are a few omissions in my edge cases, which I will rectify when I get a chance. It really is tough to enumerate all the cases!

Indeed, the digestion is most conveniently indicated through changing the piece type to a visibly different one. It is no crime in chess variants to have invisible game state (e.g. castling rights in orthodox Chess), but I think this would just invite errors in the Leaf Pile case.

It is true that 'collapsing' game-theoretically identical piece types into one would affect the repetition rule. But this seems an advantage rather than a disadvantage. What would be the use of prolonging play by allowing another set of repetitions of game states that are considered artificially different (e.g. because two Mummies got swapped)? In the end repeating the sequence of moves will swap the pieces back, with the same result. In my experience pieces almost never get swapped in games without drops. (Jocly considers pieces of the same type distinguishable when testing for repetitions, in deviation of FIDE rules, and it only started to cause problems when I implemented Shogi variants.)

BTW, I am pondering about how to make a more compact description of the rules of this excellent game. A formulation that seems to go a long way would be:

Pieces can change location either by 'Moving', or by being pushed (by a Go Away). In general, Moving is only allowed to empty, unpolluted squares. But there is no restriction on squares pieces can be pushed to; the pushed pieces will coexist there with any previous occupants. Exceptions are the Zombie (which can Move to any square, and then destroys all pieces that were there before), and the Leaf Pile (which can Move to unpolluted squares containing only mobile pieces). Zombies cannot coexist with Ichor, and the two agents destroy each other. Leaf Piles digest all pieces that try to coexist with them; when two Leaf Piles meet the stationary one is digested. Removal of pieces due to failure to coexist happens automatically at the end of any turn.

About the UI issues with Go-Away pushing order: wouldn't it be a natural interface to highlight all adjacent pieces after ordering a push by clicking the Go Away twice (as already has to be done now), and then allow the user to 'click them away' one by one?

And some thoughts about compulsion:

Replacing a Ghast compulsion by a lesser one (at greater distance) was explicity declared to be legal. The other two types of compulsion do not exist in grades. (Although they could, depending on the age of the Ichor or the number of pieces in a crowded square.) It was not specified whether it was legal to replace one type of compulsion by another. E.g. when a piece is pushed from an ichorous square onto a Ghast square, is the compulsion addressed? And when the reverse happens? What if a piece gets pushed to an ichorous Ghast square? Can you resolve that by pushing it to an empty square closer to the Ghast? Or would you have to address all pre-existing compulsions on the same piece simultaneously?

I would be inclined to require that, with the exception of getting a lesser Ghast compulsion, the piece should be free of all compulsions after the move in order to count that move as legal.

The observations that certain pieces become effectively neutral in color on petrification, and that a petrified Go Away is identical to a Mummy, are almost true. However, if one were to actually make such reductions during play, information would be lost as far as counting repetitions of positions goes.

Unrelated but worth mentioning while I'm here: in my Nemoroth implementation, there are really two Leaf Pile piece types, normal and "digesting." A normal Leaf Pile becomes a digesting Leaf Pile upon engulfing a piece, and a digesting Leaf Pile reverts back to normal when it moves of its own accord (i.e. not as a result of a Go Away's scream). It's rather important to keep track of this state, or you won't remember whether the Leaf Pile is supposed to leave behind a Mummy. This is an unfortunate omission from the otherwise fine scheme in the "Nemoroth Notation" article by John Lawson -- I would suggest using a "d" prefix to indicate digestion, such as in "dL."

Some Nemoroth pieces are 'color blind': they capture or otherwise affect friendly and enemy pieces in exactly the same way. The only effect of their allegeance is then which player is allowed to move them. But when they are petrified neither player can move them, and in effect they become neutral. An alabaster and an obsidian Leaf Pile are really the same piece, from a game-theoretical point of view, and that also holds for petrified Wounded Fiends. Likewise petrified Go Aways are all the same. And since they lose their special power on petrification, they are also the same as a Mummy. And they only differ from petrified Humans when we adopt the rule that petrified Humans promote to Zombie when pushed to last rank. Which would also make it necessary to distinguish petrified Humans by color.

Petrified Basilisks remember their allegeance because of the Basilisk's asymmetric move, which is preserved in the way it sees. Ghasts have a more severe effect on foes as on friends.

I have published both and removed the page for the old preset.

I repost also this message: This page is done too. It sends to a Game Courier preset with enforced rules for Wild Tamerlane. It could replace an existing page with the same title, https://www.chessvariants.com/play/wild-tamerlane-chess, which points to a Game Courier Present not coded with no rules enforced.

W^B is referred as Manticore on CVP. An Aanca is F^R, Gryphon here. This is an old tiring discussion.