The site has moved to a new server, and there are now some issues to fix. Please report anything needing fixing with a comment to the homepage.



The Chess Variant Pages




[ Help | Earliest Comments | Latest Comments ]
[ List All Subjects of Discussion | Create New Subject of Discussion ]
[ List Latest Comments Only For Pages | Games | Rated Pages | Rated Games | Subjects of Discussion ]

Comments by Bn Em

Later Reverse Order EarlierEarliest
Riftwalker Chess. Hidden A 4 dimensional game on a 3x3x3x3 board. (3x(3x(3x3)), Cells: 81) [All Comments] [Add Comment or Rating]

Since this comment is for a page that has not been published yet, you must be signed in to read it.

Tenjiku Shogi. Fire Demons burn surrounding enemies, Generals capture jumping many pieces. (16x16, Cells: 256) [All Comments] [Add Comment or Rating]
Bn Em wrote on 2023-01-28 UTC

Playing about with this diagram I did seem to have run into some strange bugs:

  • Passive burning works correctly, but not when the promotion dialogue turns up. E.g. Rook General g4xg13 from the opening setup survives even though it lands next to the Fire Demon. If I promote it then move it next to the FD again it's burned as expected
  • Under certain conditions (it seems to be contingent on whether it's a piece's first move), promotion seems to become corrupted: it gives me the promotion dialogue, but doesn't promote it regardless of which option I select. Subsequent moves allowing promotion (into/within/out of the promo zone) likewise ask but don't react, and the move seems to permute surrounding pieces in an unpredictable way, often with the same highlighting as for burn victims, though sometimes on squares with pieces still (or newly) on them. I think this is contingent on whether it's a piece's first move:
      1. RGg4xg13=GG works (besides the above bug allowing it to survive)
      1. Pg5–4 Pg12–g11 2. RGg4xg13 similarly works
      1. Pg5–4 Pg12–g11 2. RGg4–g5 Pg11–g10 3. RGg4xg13 triggers the bug

The two bugs together also mean that a piece subject to the second bug can never be passively burned within the promotion zone


Interactive diagrams. (Updated!) Diagrams that interactively show piece moves.[All Comments] [Add Comment or Rating]
Bn Em wrote on 2023-01-28 UTC

The Queen burns like a Fire Demon here

Did you mean including passive burning as well? Only active burning is working for me (though Adam's Tenjiku diagram seems to implement passive burning too so clearly it's implementable as you described)


Diagram testing thread[Subject Thread] [Add Response]
Bn Em wrote on 2023-01-19 UTC

The KAD goes back at least as far as the Pasha of Paulovits' game, and also appears as a Mastodon in Mats Winter's games and as Joe Joyce's Jumping General (How's that for alliteration?(!) )


Man and Beast 10: The Hybrid Diagonal. Systematic naming of straight coprime hex-prism-specific radial pieces.[All Comments] [Add Comment or Rating]
Bn Em wrote on 2023-01-13 UTC

This is very true, though a bit out of scope for M&B; while 3D boards seemingly fascinated him, Gilman apparently had no interest whatsoëver in 4D games as they are too far removed from human experience

Fwiw it's not only the Rumbaba (and ofc the Dicorn, Rumchick, extra Generals, ⁊c) that turns up on a Tesseract‐cell board: some of the (in 2‐ and 3D) hex‐specific leapers like the (1,1,1,2) Sennight (or perhaps it's a Foal? here with 64 directions) do too, though I think the likes of the (1,1,2,2) leaper might've needed a new name


ChessVA computer program
. Program for playing numerous Chess variants against your PC.[All Comments] [Add Comment or Rating]
Bn Em wrote on 2022-12-20 UTC
  1. The turn pass is considered a move of the King

Option 2b: the turn pass can be made by any piece (or any piece w/ a pseudo‐legal move) on the passing side. And is thus, for mate‐detection purposes, equivalent to the intersection of all such moves.

This has the advantage of needing less off‐board state to be maintained: you only need to record what the opponent's last move was, not your own (as with e.g. en‐passant or lion anti‐trading); also a Joker cannot then give check as a piece no longer on the board, which I find a mildly surprising behaviour, and the position in Greg's diagram is unconditionally checkmate. It also matches my proposed update‐on‐touch‐move semantics, which covers castling out of or moving through check, even in the presence of multiple differently‐moving castling‐capable royals, as well as a possible rule for interacting w/ e.g. Orphans

Conversely, opt. 1 has the advantage of being considerably easier (I imagine) to implement, and probably to explain, at the expense of in some ways exhibiting more surprising behaviour. And Daniel's equation of it with a double move makes some sense (though given the context of actual double‐move variants there are possible quibbles). I imagine it'd be the most popular option.

I agree that of the options H.G. listed, 1 seems most natural; I find my opt. 2b a touch moreso, but opt. 1 is not far behind, so people's mileage may (and probably will!) vary


Bn Em wrote on 2022-12-19 UTC

Ok, if there are no objections, this will be the behavior of the ImitatorRule in ChessV

No objections from me

as I said, this whole issue is a moot point. You could probably play hundreds of games before you encounter a situation where a Joker check would or would not make castling illegal or would checkmate or stalemate depending on this.

In general I don't think much of rules or rule complications that have next to zero effect on actual game play. I would always go for simplicity when it does not matter.

It's effectively moot in the Apothecary games, sure. Nevertheless it's not so difficult to contrive games where the issue would carry greater importance: consider a game featuring both a joker and an orphan. Such a game would have an equivalent problem with determining under which conditions the joker threatens — and thus relays moves to — the orphan, which one would imagine would have a substantially greater effect on gameplay (especially if it's a gimmick game with several of a few different imitators).

The latter case is (much like the orphan itself, and perhaps even the joker) ofc of even greater interest to problemists than variantists, and they don't really tend to have much of a presence here


Bn Em wrote on 2022-12-19 UTC

Yes, I'm sorry, this is more complicated than I'm prepared to implement

I expected as much :)

I'm concerned people won't sufficiently understand it

That is my main reservation with it as well

Look how hard it has been to even get everyone understanding the current issue, and we are all experienced players of chess variants

To be fair, most variants are in this respect noticeably simpler; temporal imitators raise some very subtle timing‐related issues that ‘normal’ pieces can easily ignore

H.G. did present another idea which we could call Option 4 - for purposes of check determination when the other side is on the move, the Joker is always considered to move as a King

Indeed, I saw. For moving out of check, this proposal is equivalent to mine as H.G. has since noted; for mate, it differs only in that the null move (per H.G.'s explanation) can be performed by any piece (with a pseudo‐legal move — though I suppose it'd be a valid simplification to allow it to simply be any piece), not just the King.

(But I don't think this will be a popular option.)

Indeed; it seems a tad artificial to me. My proposal eliminates a bit of the artifice at the expense of some definitional clarity. Which is a tradeoff that I can understand one might be reluctant to make (especially if, as in your case, one finds the J distasteful in any case ;‌) )

If you add a Joker to Xinagqi, how does it imitate the King? Is it restricted to the palace? If it is not currently in the palace, can it move? Does it "check" the opponent king across an open file? Only in the palace?

That depends on how much of the restriction is considered to be a property of the General and how much is considered a general game rule. There's no general consensus on where that line lies; I think all of the particulars you list have been interpreted in a variety of ways by different extrapolations


Bn Em wrote on 2022-12-19 UTC

The ‘castling out of check’ case suggests to me another definition again: if we consider the restriction on castling out of check to be an extension of the restriction on moving through check — in effect that the K can be captured en‐passant on its starting square, upon having decided to move — then check for castling purposes would always be calculated with an effetive K move for the joker. Iow the move of the J, and whether it gives check, is defined at ‘touch move’ time.

For the case of determining checkmate or stalemate, that would mean that the J would give check with the intersection of the moves of all pieces able to move pseudo‐legally. As such KJK would still lead to checkmate, but with most other combinations of material the J would not give passive check at all. But in e.g. KJKQ the J would give passive check as a K. With more complex pieces (esp. those that can be blocked — particularly the Vulture of the large Apothecary games) this would potentially be position dependent. (And I think it's a little subtler yet in the hypothetical case of a game with both a joker and two royals with disjoint movesets)

Ofc this is probably horribly inefficient to program, provided it's even deemed to make sense (I like it for castling‐out‐of‐check restrictions, but I'm ambivalent between it and Option 2 (by Greg's numbering) for check‐/stalemate — it avoids the surprising(?) behaviour of HG's example where the J checks as a piece that's no longer on‐board, in exchange for arguably slightly greater opaciity of definition), so take it or leave it :‌)


Enchanted Forest. Hidden Chess Variant with fairy pieces. (8x8, Cells: 64) [All Comments] [Add Comment or Rating]

Since this comment is for a page that has not been published yet, you must be signed in to read it.

Fluidity Chess. Hidden Dissect the pieces. Standard board without pawns. (8x8, Cells: 64) [All Comments] [Add Comment or Rating]

Since this comment is for a page that has not been published yet, you must be signed in to read it.

Revisiting the Crooked Bishop. Revisiting the Crooked Bishop.[All Comments] [Add Comment or Rating]
Bn Em wrote on 2022-11-26 UTC

Fergus asked some time ago whether a piece covering the same squares as a zB but alternating between the move's arms (for which he suggested the name ‘Helical Bishop’ on account of the path's resemblance to a DNA‐style Double Helix) had already been invented. It seems we can now answer that in the affirmative: it's mentioned twice on this page, as the Zigzag Bishop. Betza also posits what Gilman would go on to call a Bruegel (t[Wzt[FAA]]; for which I initially mistook Fergus' description), as well as a piece (the t[FzDD]) ‘dual’ (in the Gilman sense) to the Harvestman of Seenschach which seems to go curiously unnamed in M&B.


Tiger Chess. A large game with fast-moving pieces.[All Comments] [Add Comment or Rating]
Bn Em wrote on 2022-11-24 UTC

It's ‘outward’ in the same sense that the Shōgi Knight moves ‘forward’; only the most outward of the directions counts.

Arguably could be specified more clearly, but the diagram does imo clarify sufficiently which sense is meant


Majority Chess. You can move a piece only if it is on a file where you have a majority of pieces. (8x8, Cells: 64) [All Comments] [Add Comment or Rating]
Bn Em wrote on 2022-11-17 UTC

A potentially interesting idea, though I haven't had the chance to play it

But the first example is misanalysed: Bf3 is not Stalemate, but rather illegal as it equalises the number of pieces on the e file, allowing the black queen to move and give check to white.

The assertion about the e file wrt the f4 pawn is presumably a typo.


Expansion Chess. Hidden Get points per each your piece on other half of board to win. (8x8, Cells: 64) [All Comments] [Add Comment or Rating]

Since this comment is for a page that has not been published yet, you must be signed in to read it.

Chess 66. Board based on the 8x8 arrangement - with the difference that 66 fields are now available. (8x8, Cells: 66) [All Comments] [Add Comment or Rating]
Bn Em wrote on 2022-11-15 UTC

But why can't a bishop from d1 move to A4 and what am I still overlooking here?

It can; the discussion was whether a bishop can move from e8 could move onto both of a4 and A4, whereas it ought only to be able to move to A4; from f8 it could instead move to a4 but notA4`.

Should the description consider the following knight moves? Knight on b3, is the move to a5 possible, because on the same diagonal? Or a knight on a3, are the moves to a5 or b5 possible, because on the same line?

That depends on the definition of the Knight move: by the subtractive definition you and Fergus have used, those would be disallowed as a Queen could move to those spaces, as you've noted. Other definitions (such as the traditional ‘one orthogonal step then one step diagonally outward (or vice versa)’) would include those squares.

Which definition you prefer is in this case up to you


Bn Em wrote on 2022-11-13 UTC

You can certainly scrap the entire concept.

I'm not sure which part of my comment you took as scrapping anything; certainly that was not the intent. Merely a minor note that your use of the word ‘maximum’ implied a liimitation I don't see

Mind games should be able to be discussed. Or do you have a different opinion?

I fully agree; if I differed in opinion there would be little reason for me continuing to frequent this forum. Did I imply something else?

At the beginning of the discussions, I was of the opinion that switches work differently when they are operated from below, from the side, or from above. I have abandoned this opinion and changed it in favor of a pragmatic solution, in that a switch must be handled the same regardless of the direction.

From what I remember, the discussion was limited specifically to movement via the side of a switch space: your original description allowed (rook) movement from A4 (using Fergus' notation) along the rank to e.g. b4, but not vice versa, breaking the usual assumption that slider moves are reversible. The ‘pragmatic solution’ you refer to was specifically to allow orthogonal slides from/via b4 to reach either of A4 or a4. It might be noted that disallowing all sideways movement from A4 would have achieved the same effect.

As far as I remember entry from the top of a switch, orthogonally or diagonally, was never controversial in this way, and as Fergus has noted unifying downward entry in the same way as for sideways entry leads to exactly the problem of asymmetry that unifying sideways entry was supposed to avoid.


Bn Em wrote on 2022-11-12 UTC

At the maximum

If we're extrapolating already, why stop there? You could always get the 3rd and 6th ranks involved too, maybe even the 2nd and 7th if you don't mind the pawns starting on switches…

And/or you could have some more switches of the Chess 69 variety along the top and bottom if that's not enough strange topological shenanigans.


Setup graphics, piece sets[Subject Thread] [Add Response]
Bn Em wrote on 2022-10-09 UTC

The obvious remaining reason to favour static images over the interactive diagram is that the latter only works with Javascript enabled. I suppose the obvious(?) way around that would be to also have the design wizard generate a link to a Diagram‐Designer‐ or Scalable‐Diagram‐Editor‐generated (if the latter gets installed?) image and wrap it in <noscript> tags?

P.S. There is something very strange with the title of your posting, which is not equal to the title of the subject thread.

The same is true for the first two comments to be moved to this thread, when viewed through the main comments page (EDIT: and apparently this comment too; the comment editing form has the following warning above it: The ItemID 836609b4fd3c40eb no longer matches any item in the Item table.)


Skica. (Updated!) 10x10 with Ski Pieces and Camels. (10x10, Cells: 100) [All Comments] [Add Comment or Rating]
Bn Em wrote on 2022-10-09 UTC

At least for the Knight case I'd tend towards yes, with a qualifier for Leaping and (the small variety of) non‐leaping versions (a mao might be Chinese‐style, or orthogonal‐first, for ex.; the moa diagonal‐first, and their compound the ‘moo’ two‐path (or perhaps, following Gilman, Flexi‐path?)). Again, both elephants/dabbabas and Chinese/Korean Cannons (the latter of which arguably differ yet more fundamentally) are usually referred to this way, and the only naturally‐occurring mao is cognate to the leaping knight

As for the leaping Rook (iirc it exists in Ramayana Chess as the Buddha)… quite possibly too; it's renamed in that game most obviously because all the names are themed, and since none of the pieces are blockable it's as easily just a rule difference as a fundamentally distinct piece. At least Gilman took the same attitude for Dabbabantes and their ilk

The main exception for me is if the two are present in the same game, in which case different atomic names start to make sense (indeed even for pieces that move identically but have different behaviours outside that, e.g. promotion or royalty); and indeed while they might feel quite different to play with, it'd seem odd imo to have an array with both leaping and non‐leaping ski‐bishops, or early‐ and late‐turning manticores. Ultimately it's probably really a matter of not arbitrarily proliferating unrelated names for uncommon pieces with more (imo) similarities than differences

And yeah, M&B took me several reads before I got to the point of more‐or‐less understanding (especially since there's plenty of stuff in there that's more interesting than the reams of names), and the broken diagrams are at best distracting


Bn Em wrote on 2022-10-08 UTC

Ski‐ is a nice prefix for general use (though compared to Grant Acedrex's Ski‑manticore, the Tiger Chess astrologer is perhaps less obvious as a ski‐ piece since it arguably jumps over two squares — in the same way the osprey is arguably a ski‑‘2.manticore’, to use Aurelian's term for lack of anything better), but it does make sense imo to have separate words for the simplest ski‐ pieces; Bicycle/‐reme/‐plane are nice enough in that they extrapolate easily for longer initial leaps (tricycle, pentareme, ⁊c., practical utility aside).

Fwiw, I tend to agree with Gilman's conflation of jumping ski‐bishop with Tamerlane's non‐jumping Talia/Vanguard/Scout/Picket (he selects the latter term), on the grounds that they reach the same squares, like leaping and non‐leaping elephants; the leaping is then distinguished by a prefixed word (that said, I would tend to similiarly conflate normal and contra‐gryphons and Renn cavaliers for the same reason, so I suppose that can be taken with a pinch of salt given general tastes here). Fwiw he also has an ‘‐on’ suffix for extending a radial leap into a subsequent slide (such that ski‐bishop/picket ≡ ‘elephon’, ‘trilbon’ ≡ notional ‘tri‐plane’, and things like Sowons (per Long‐Nosed Generals) are possible) — though he doesn't touch oblique‐starting pieces.

As regards atomic names, his ski‐queen ≡ Fagin avoids clashing initials, albeit being a bit of a specific reference; Picket and Pocket (≡ ski‐bishop/‐rook) have no such luck, though Picket is always substitutable as above (and both T and V are relatively uncommon initials for CV pieces) (and also, Bat does in fact have a prior usage, as does Quetzal)


Alexander Chess. Hidden A more battle-like version of chess. (10x10, Cells: 64) [All Comments] [Add Comment or Rating]

Since this comment is for a page that has not been published yet, you must be signed in to read it.

Grand Riders Chess. Hidden Chess with cross over between Cavalier Chess and Shogun Chess and use the normal riders.[All Comments] [Add Comment or Rating]

Since this comment is for a page that has not been published yet, you must be signed in to read it.

Since this comment is for a page that has not been published yet, you must be signed in to read it.

ArchMage Chess. Hidden 10x10 30v30 Fantasy Chess. (10x10, Cells: 100) [All Comments] [Add Comment or Rating]

Since this comment is for a page that has not been published yet, you must be signed in to read it.

25 comments displayed

Later Reverse Order EarlierEarliest

Permalink to the exact comments currently displayed.