Comments/Ratings for a Single Item

A definition that would get rid of the non-reciprocity, would be that the Friend can make any move of a piece that could capture it if friendly capture would be allowed together with any normal capture. It is probably a matter of taste, but I feel that this definition.

From the diagram I take it this is allowed only when moving to Alibaba destinations?

That's correct; the Ghost goes to "the next square beyond."

I am not sure whether [allow[ing] moves of one piece to be relayed from Friend to Friend through moves borrowed from another piece] was the intention of the original definition

It seems none of the info on the CVP, including Orphan resources (which could in principle provide analogous situations) such as the Helpmate problem and the (Wayback Machine copy of) the Torsten Linss problems (linked from the Piececlopedia article), is able to clear this up, and short of finding back‐issues of the British Chess Magazine info on the web seems very elusive

The only other source I could find offhand was Die Schwalbe's glossary, which also doesn't really clear anything up (though it does give rules for initial pawn steps, at least for Orphans: an Orphan may make a double step from its second rank, but only a single step from its first)

Among the freely available Schwalbe issues, a few feature Orphans but apparently none feature both multiple normal pieces that could relay distinct moves and Orphans on both sides that could chain. Friends seem to be completely absent from these issues (indeed, any of the issues whose indices are available), though still present in the Glossary (which clarifies that, at least for the Schwalbe, the Friend explicitly can't promote with a pawn move to the far rank)

Would be interesting to see whether the BCM or Brown's own problem collection made any use of this that could clarify this, but access to either is probably a pain :‌/

It would probably be better to use a 'static' definition, like "when it would be able to capture the Friend if that had been an enemy pawn".

If only direct move pass‐through is allowed as you suggest, this seems uncontroversial; in the case with indirect relay I'm not sure whether that makes the non‐reciprocal passing on (assuming it remins desired — I quite like it myself) more complex to formulate correctly than reciprocal passing on. In principle that same question arises for the Orphan too, though I imagine the chances of finding a problem that relies on either of those possible behaviours is incredibly slim

[The Ghost] captures by "passing through" an adjacent square on its way to the next square beyond

From the diagram I take it this is allowed only when moving to Alibaba destinations?

I'll get on that "Guarding" thing when I next go into editing this; thank you for the note.

The Archer is less devastating (even though I would not be surprised if it was as valuable as a Queen), because it can only rifle capture from nearby, so it cannot do it from cover.

BTW, your definition of 'guarding' is a bit murky. What if white has Rook at a4 and Friend at h4, while black has a Rook at e4? This makes a4 what the Chu-Shogi rules would call a 'hidden protector', as after black's Rxh4, it would be able to recapture that Rook. So can the Friend borrow the moves from that Rook? I guess that is not what you want, but your definition is not clear about that. The reverse case would occur if there was a Cannon on a4. After Rxh4 the Cannon now cannot recapture that Rook.

The point is that the possibility to recapture is a dynamic thing, which depends on how you captured. It would probably be better to use a 'static' definition, like "when it would be able to capture the Friend if that had been an enemy pawn".

OK, I see what you mean. And the Archer already offers a rifle capture, so the Sniper doesn't really add anything to this.

I probably should replace the Sniper, then. What with, do you think? A Gryffon, or some other bent rider?

EDIT: Never mind; I have the answer: Ghost!

UPDATE: I've fully replaced the Sniper with the Ghost, except for the setup diagrams (which are a major chore that will have to wait).

I still want to use the Sniper some time, but it'll be as a promotion.

The problem is that it takes time to chase the Sniper away, and by the time you have done it, you are 3 pieces lighter. And by that time there was nothing left to snipe at anyway, so the Sniper happily moves to a new location where it forks another 3-5 of your pieces, for the next round. Pieces like Midnighter, Impala or Gerbil are not very manouevrable; it takes many moves for them to renew the attack on the Sniper when it just steps one square. And any move you use to let your most important pieces flee from Sniper attack cannot be used to launch an attack on the Sniper. (And attacking the Sniper with the distant leap of the Impala is suicide, as the Sniper has that move too, and just takes it out.)

Attacking a rifle piece is indeed the only way to defend against it, but it is a woefully inadequate defense, which just gets you slaughtered.

You should really try this out with an ID; even if only with one that doesn't have some of the more exotic rules of this game, to guage how devastating Snipers are even if you don't have any Friends to amplify them.

Well, as I say in the description, this is largely an exaggeration for illustration, even though I'd love to try a face-to-face version.

I'll go in a little later and address at least the first three notes you gave in the text. (I know I need a better word than "Displacer," since "displace" is also a type of capture around here. I'm open to suggestions there before I go and upload a bunch of pieces with the ability.)

As for the Sniper, in this case it gets worse than that. The Snipers don't need to be centralized; a Sniper can stay safely in its spot, and Friends relay the shots all over the board. For this reason, I'd strongly recommend against having a Sniper and a Friend (at least, more than one) in a game with conventional checkmate. As it is, if the Sniper's power gets to be a problem in the game, the opponent may just need to find a way to take it out, perhaps using a Midnighter, Impala, or Gerbil.

Beware that "nightmare to program in software" and "nightmare to play" could be pretty much the same thing.

But I am not sure that this isn't an exaggeration, as most features of this game already can be handled by the Interactive Diagram without custom scripting. What cannot be done is often very similar to what is already done; e.g. the ID does support spells, just not two different spells at the same time. It doesn't support a Friend, but this is similar to move induction. Borrowing of special powers adds some complexity to this piece, but Rifle and withdrawer capture are just moves; I would not describe those as "special powers". (Which makes it all the more strange you exclude borrowing of e.p. capture...)

Multiple spells might be a nice feature to have anyway. The ID implements spells by tracking the location of pieces (maximally two of each type, but in cases where there are more you can articicially split the type in two identical types), so that you don't have to scan the entire board if you want to know where pieces of a certain type are. For its normal operation this isn't needed, so it is only done when spells are defined, to easily locate the sources of the spell. This switches on tracking of all piece types; that you have to specify a piece number in the parameter trackPieces=N is only to indicate which pieces cast the spell. When multiple spells are to be supported, it obviously should become possible to specify the type of spell on a per-piece basis, and this would make the trackPieces parameter redundant; tracking could automatically be switched on if any of the participating pieces casts a spell.

The way the spells work now is that before starting move generation in a given position, it goes through the list of spell-casting pieces, and marks a 'neighbor' board to indicate which squares are in the spell zone of those. The move generator has tests in places where its action could be affected by a spell (such as when it gets to a new piece, testing if that piece is immobilized, and aborting the generation of its moves when it is), to see if that spell is in force, and if so, whether the square is in its zone by consulting the neighbor board.

For implementing multiple spells there should just be a separate neigbor board for each spell flavor; the move generator would then not have to test whether the spell that would affect its decision at that point is in force, but can directly test the square on the neighborhood for the applicable spell. So for the origin square it would test the 'freeze' neighbor board to see if any moves must be generated for the piece at all, on a square reached by a slider the 'brake' neighbor board, to see if sliding can continue, etc.

When going through the spell-casting pieces it would then mark the spell zone for each of those in the board belonging to the spell that piece casts. Whether each piece should be allowed to have a different spell zone as well as a different spell, and whether a single piece should be allowed to cast an arbitrary combination of spells is a good question. For this game that would not be needed, provided Hia power would be on the spell menu as what currently is 'brake' in combination with 'slow'. So if we defer that to later date, the modification required for allowing different spells by different types, all with the same zone, in one variant, is really quite minimal.

That leaves the Friend. This would require a special algorithm, because you apparently allow moves of one piece to be relayed from Friend to Friend through moves borrowed from another piece. (I am not sure whether this was the intention of the original definition; you already get relay chains if piece moves can only be relayed through moves of that piece type, and this would be a lot easier to program.) The way I would handle it is first generate all the moves of the other pieces, but record for each Friend which pieces had moves that were hitting it. This could actually be handled by replacing all Friends by some innocent enemy piece, so that the moves hitting it appear as captures of those in the move list. Afterwards you could then run through the move list to collect all moves that were capturing to the Friend's location, to build the list of its protectors, and delete the moves from the move list.

The next step would go through all Friends, and for each of those generate the moves of all pieces that were hitting it. Still under conditions where the Friends are replaced by enemies. If amongst the moves this adds there are captures to the Friend squares, you would merge the list of attackers of the protected Friend with that of its protector to get the new list of the hit Friend. And you would remember if this really added any new pieces. If any of the Friends would acquire new moves because of that, you would delete all the Friend moves from the move list, and repeat the process with the new capabilities.

If you no more changes to the lists of mimicked pieces occur, you finally delete all the moves to the Friend squares from the move list, and put the Friends back in their place. If there are not too many piece types (say 30) , the lists of capabilities could conveniently be made as a bitmap, where each bit in an integer represents a piece type, and gets set to 1 of the Friend mimics that piece type. Merging the lists can then be done with bitwise logical operations.

Of course the borrowing of the spell-casting abilities as part of mimicking would require conditional marking of the neighbor boards for those spells by Friends, depending on what they are mimicking. Which must be calculated here during the opponent's turn (as the involved spells are of the type that affect enemies), where it would already have changed compared to how it was before the preceding half-move. So you would have to re-run the opponent move generation, including the Friend chaining, in order to know which Friends cast spells.

I have my doubts whether this 'Recursive Friend' makes a nice game for humans, so I am not really eager to have the ID support it. I am leaning to a simpler version of the Friend, where it only relays the power to mimic a piece through the move of that piece. In that case the move generator, whenever it hits a new Friend, can immediately continue generating moves for that Friend according to the same prescription. That seems more manageable for humans too. We want to avoid the emergence of a new proverb "the Friend is your worst enemy"!

Some remarks on your description:

• Can a Friend attacked by a Pawn promote? You don't mention that, but promotion should certainly be considered a special power...
• W.r.t. the Squirrel, 'displace' can mean anything, but somewere burried down deep it turns out you actually mean 'swap location with'.
• Better explicitly state that the withdrawer capture is optional, and not a mandatory side effect of the move, as this is quite unusual.
• The distant rifle captures might be insanely strong. As they can be made from a safe distance there is basically no defense against those other than moving the attacked piece away. But they have good forking power. So the game might degenerate into quickly centralizing the Snipers, and massacring the opponent with it.

…or fellow Bodyguard?

Good catch, that. I generally write these things with the assumption that the Bodyguard will stay in the back and play defense, but there's no real reason that one couldn't try to make a play for the center or even the far end.

But how would that other friend get there? Surely if it got there on its own volition it would be considered to have moved, meaning can't have and therefore can't transmit the initial Pawn moves?

This would require that the move be passed on from another Friend, who is in range of both the Pawn and whatever piece that Friend is using to transmit the move. The Friend transmitting the move can have moved, and pass it on to the Friend in question; the restriction against having moved is on the recipient.

Does a Squirrel Displacement not count as movement for the piece being displaced? That would solve this, though it'd also make it possible (indeed necessary for the chain) for a Friend to gain the initial moves directly

For purposes of an "opening move," Displacement does count as a move. (This decision is not final.)

So to be clear (purely for my benefit, as I was thrown the first time I read it), the Squirrel can still capture enemy pieces normally?

Yes, that's correct.

Iow a Friend captured whilst under the guard of a Poison annihilates its attacker? Is this optional (in the rare case, such as blocking check(mate) that waiving it would be desirable)?

I probably should make it explicit one way or the other. Probably the Poison (and Jellyfish) would be automatically poisonous, making this answer "no, not optional."

Hia could be optional, though; that seems like something that a Bodyguard could "turn off" if desired, though I'm not sure why one would. The rifle and withdrawal captures are already optional for the host pieces.

And this is why I didn't use Zombie Pawns in this game!

I have to say I like this a lot. It's a shame it looks like a nightmare to programme; looks like playing it would be a fascinating experience :‌)

Thanks! And yes, it'd be an absolute nightmare to program in software, for more reasons than I want to think about. I personally would want to play it in person! It may be most practical to play by conventional email. But even if nobody ever plays it in any mode, at least it'll give readers something to think about.

While Brown found the Friend uninteresting from a chess-problem standpoint, I think it has great potential

It seems to me that, especially in these larger numbers, the friend may work much better in games than problems for the same reason that the Orphan and Joker are perhaps more suited to problems: they lack the interplay between the sides, and thus the owner has actual control over their deployment. Orphans and especially Jokers would need enough sufficiently mobile pieces on the board that it's hard to avoid granting them power (somehow not unlike Contramatic Chess. Hmmm…)

Any sliding piece — Archer, Caliph, Lady in Waiting, Mtawala, or Sniper, as well as a Friend trying to use their moves

…or fellow Bodyguard?

A Friend only gets the special initial moves of a Pawn if neither the Pawn granting the ability nor the Friend has moved yet (meaning it can only be done with the help of another Friend).

But how would that other friend get there? Surely if it got there on its own volition it would be considered to have moved, meaning can't have and therefore can't transmit the initial Pawn moves?

Does a Squirrel Displacement not count as movement for the piece being displaced? That would solve this, though it'd also make it possible (indeed necessary for the chain) for a Friend to gain the initial moves directly

the Friend can also receive […] the Displacer Squirrel's ability

So to be clear (purely for my benefit, as I was thrown the first time I read it), the Squirrel can still capture enemy pieces normally?

the Friend can also receive […] the Poison's poison

Iow a Friend captured whilst under the guard of a Poison annihilates its attacker? Is this optional (in the rare case, such as blocking check(mate) that waiving it would be desirable)?

Similarly, are rifle‐capture and/or withdrawal optional, if the friend is also borrowing from a piece that can make the same move w/o the special power? And (if only for completeness) what about Hia power?

gain[ing] moves and abilities from another Friend […] isn't necessarily reciprocal

This is a nice detail, which I'd missed in mỹ own thoughts about this piece. It'll be hell to keep track of though, especially if the false guard is by a third or fourth friend

Any piece adjacent to a Jellyfish cannot move, including leaps, slides, and rifle captures. However, unlike the case with the Bodyguard, this does not affect pieces merely moving past the Jellyfish

I've been meaning to put together mỹ own showcasse game for the (in my case catch‐only) Bodyguard (it's a really nice piece) and was likewise going to include a traditional immobiliser — I find the duality between a piece that impedes long range movement but allows escape and one that completely traps things but allows passers‐by quite pleasing :‌)

Normally, the Friend doesn't gain any of a piece's "special moves" at all, and under Mr. Brown's rules presumably wouldn't gain any special abilities from other pieces either. I've altered that rule for this game; pieces like the Bodyguard, the Displacer Squirrel, and the Jellyfish are here specifically to explore the possibilities.

Strictly speaking, having gone hitherto entirely unused, there's no precedent at all here, and I wouldn't be surprised if Brown's Orphan problems also lack other pieces with special abilities, leaving no precedent there either. And even the Joker, while more popular, tends (I can't recall any exceptions offhand) to be paired only with relatively orthodox pieces…

Of course the interaction of special powers with Orphans and esp. Jokers is substantially more complicated (what does it mean for a joker to imitate Hia power? Not that I don't have mỹ own interpretation…). We'll have to leave that for a notional ‘Grand Imitator Chess’ — I'll certainly give that a go eventually

I have to say I like this a lot. It's a shame it looks like a nightmare to programme; looks like playing it would be a fascinating experience :‌)

• It's better to put in quotes the word "Chess" ))))
• You've missed the typo in Sniper description: text is 2,3 when image shows 3,4

My thanks, on both counts.

• It's better to put in quotes the word "Chess" ))))
• You've missed the typo in Sniper description: text is 2,3 when image shows 3,4

How about if I just put the word "Friendly" in quotes?

OK Bob, I see your point, you take the word "chess" as a generic term for any chess-like game. But for most people chess with no epithet is international chess and "a game of chess" is a particular game of international chess between 2 players.

Wouldn't something like "A friendly chess variant" be better? Or "A friendly fairy chess"?

The doubling of the A was an accident, earlier this morning, as I was trying to fix the lack of an A in the title. (And now the opposite problem is happening!)

A single "A," as the intent, had that evocation (a game a chess that's friendly) deliberately; it hopefully would invite curiosity, and of course the Index information about using the piece called a Friend should help.

I find the title very weird. First it comes as "A a friendly game of chess", doubling the "a". I can catch the idea but the resulting output is not good, at least to my eyes. Then, entitling it a "friendly game of chess" evokes to me a mere of game of chess which is friendly, not a chess variant at all.

Take this just as a feedback (you asked for it), feel free to ignore it.

OK, I think this is almost ready for approval. I'd just like a couple of opinions from the peanut gallery: specifically, which of the two setup diagrams shown would be better? I think it might be simpler to just dump the first one and go with only the second. (Or, do the second but on a 16x12 board so there's more room to maneuver.)

This isn't quite ready for posting yet (I fully intend to include move diagrams with this one), but it is ready enough for feedback and commentary.