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Kamikaze Mortal Shogi. Send your Kamikazes on suicide missions in this Shogi variant. (9x9, Cells: 81) [All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2022-05-23 UTC

My guess is that forbidding kings to face each other would not help. Exposed kings get checkmated very quickly in Shogi. So when the manage to cross it is always surrounded by a group of friendly pieces, from which they are chased out, and then again get new pieces dropped around the to survive.

I could imagine that the Kamikazes present the same problem as Pawns, when you are allowed to drop more than one of those in the same file.

Fergus Duniho wrote on 2022-05-22 UTC

Ever since I played a game with Greg that ended in an impasse, I felt this game may be too drawish, and I've sometimes considered changing the rules to fix this. The rule change I was thinking of was to forbid Kings from crossing to the other side of the board and to give them the ability to check each other from a distance, as in Eurasian Chess. However, it has come up that Shogi has its own rule for handling impasses, and there are alternatives to it.

The rule in Shogi is if each King has moved to the opponent's camp, which is the ranks the opponent's pieces start on, players may agree that an impasse has been reached and count pieces to determine the winner. Kings count for nothing, Rook and Bishops, promoted or not, each count 5, and other pieces each count 1. A player with less than 24 points loses. Because of the piece attrition in Kamikaze Mortal Shogi, it is possible that each side would have less than 24 points. So, instead, it could be played with the rule that whoever has more points wins. But I don't like this counting solution, and others don't too.

An alternative rule proposed for Shogi is called the Try rule. This involves winning by moving one's own King to the space the opponent's King began on. I don't know if this involves moving there only if it is safe or if it becomes a condition only after both Kings have crossed into the enemy camp. I would propose making it a winning condition only if both Kings have crossed into the opponent's camp and it moves there safely.

Similar to this is the Campmate rule, which allows a player to win by reaching the last rank with his King. I would propose the same conditions on it that I am proposing for the Try rule.

Another possibility for dealing with impasse is to reverse the directions that the opponent's pieces may move when the King moves into the opponent's camp. Additionally, pieces could be allowed to treat their own camp as a promotion zone when the opponent's King is there. These changes would discourage players from moving their Kings to the other side of the board without strictly forbidding it.

One more possibility is to allow Kings to check each other from a distance but to not forbid Kings from crossing to the other side. Instead, the ability of Kings to check each other from a distance would usually prevent both Kings from crossing to the other side, and if they happened to do so by having another piece between them on the same rank, this ability would provide an incentive for leaving the King more exposed.

Parahouse. (Updated!) Shogi + Strong pieces. (9x9, Cells: 81) [All Comments] [Add Comment or Rating]
Fergus Duniho wrote on 2022-05-22 UTC

I see Campmate was mentioned in the comments to that video 5 months ago.

Fergus Duniho wrote on 2022-05-22 UTC

Here's a video on the Impasse rule. Hidetchi, who made the video, states that he doesn't like this rule, and some people have proposed replacing it with the Try rule, which says that a player can win by moving his King to the position the opponent's King started from. What you're calling Campmate is similar to this rule. Instead of just saying "No Impasse," which is kind of cryptic, you could say, "Instead of the official Shogi rule for resolving an impasse, this game can be won by Campmate, which involves moving the King to a safe space on the last rank."

Archchess. Large chess variant from 17th century Italy. (10x10, Cells: 100) [All Comments] [Add Comment or Rating]
Parker KH wrote on 2022-05-22 UTCGood ★★★★

i think so

Parahouse. (Updated!) Shogi + Strong pieces. (9x9, Cells: 81) [All Comments] [Add Comment or Rating]
Daphne Snowmoon wrote on 2022-05-22 UTC

H.G.Miller //

I have spelled out the rules exactly. Is this allowed?

H. G. Muller wrote on 2022-05-22 UTC

I mean that you cannot expect the typical reader to know any of the rules of Shogi. So yes, you would have to fully explain those rules, or at least those that also apply to your game. It makes little sense to explain rules just to say that they don't apply.

Daphne Snowmoon wrote on 2022-05-22 UTC

H.G.Miller //

Umm, so,

"The rest is the same as Shogi"

Do you mean to explain this sentence in more detail?

H. G. Muller wrote on 2022-05-22 UTC

For example, I don't think Shogi has an "impasse" rule. 

It actually does have such a rule. See for instance the Wikipedia article, which devotes an entire paragraph to it. Like 3-fold repetition impasse (= jishogi in Japanese) is both a game situation and a rule made to specify consequences for when that situation occurs.

It does not make much sense to have detailed explanation of rules that the variant at had does not have. One can doubt the wisdom of using Shogi as a reference. Many articles on CVP of course use orthodox Chess as a reference, and only describe how the variant they discuss deviates from it. But I think 95+% of the visitors of CVP will be quite familiar with orthodox Chess, while to most Shogi would be something as alien as Courier Chess or Metamachy. Even for Fergus, who must know 100 times more about chess variants than the average reader, the current description was not sufficiently clear.

So I would suggest to make a full rather than an incremental description of Parahouse in the Rules section. The current comparison with Shogi is then more suitable for the Notes section. This gets rid of the need to mention Pawn-drop mate and impasse, as Parahouse does not have those rules. It would have to mention that:

  • Pieces mandatorily promote when their move starts or ends within the zone
  • Pieces that are captured demote, change side, and get into the hand of the player that captures them
  • Unpromoted pieces can be dropped from the hand on an empty square, instead of a normal move.
  • Pawns cannot be dropped in a file that already contains one of the same color.
  • The game is won by checkmating or stalemating the opponent.
  • Perpetual checking is a loss for the checking player. (?)
  • Other (?) 3-fold repetitions are a loss for the player that last moved.

All in all that is not much longer than what you there is now.


Daphne Snowmoon wrote on 2022-05-22 UTC

Black can also be defeated by threefold repetition. So it's not like Minishogi.

Threefold repetition simply puts, 'Neither White nor Black can repeat the same situation three times.' Even if it is not repeated in succession, if the same situation is repeated twice in one game, no one can repeat the situation again.

(I have annotated the rules)

Fergus Duniho wrote on 2022-05-21 UTC

Perhaps it is a bit confusing that the Rules section actually doesn't give the rules, but the difference between the rules of regular Shogi and this variant.

No, that much was clear. It's that some rules are not spelled out, or the rules section includes some consequences of rules that are not themselves rules. For example, I don't think Shogi has an "impasse" rule. So saying "no impasse" doesn't tell me how this game has a different rule than Shogi.

H. G. Muller wrote on 2022-05-21 UTC

Perhaps it is a bit confusing that the Rules section actually doesn't give the rules, but the difference between the rules of regular Shogi and this variant. While that becomes only clear from the last remark. It could be better to start with stating "The rules are the same as for Shogi, except:", and than mention the other 5 points.

A consequence of the rules of regular Shogi is that a game where both Kings reach the enemy camp is usually impossible to win by checkmate for eithher player. It therefore has a special rule to decide the game in that case. The campmate rule here is an alternative way of deciding the game in this case.

It is still not clear to me what "3-fold repetition is impossible" means. Is it forbidden to make a move that repeats an earlier position? Does white lose (as in mini-Shogi)? Such rule are usually very unsatisfactory, even when perpetual checking is made an exception where the checker loses. Because you can often force a large material gain by chasing a piece until it is no longer allowed to repeat.

Fergus Duniho wrote on 2022-05-21 UTC

I am unfamiliar with the word campmate. Did you coin it or get it from someplace else?

Since your rules still say "No Impasse(=Jishogi)", I should point out that there is a difference between a rule and a consequence of your rules. For example, Metamorphin' Fusion Chess has rules that allow players to promote simple pieces and to split apart compound pieces, and one consequence of these rules is that reproduction of pieces is possible. Generally, a rule should be written out as a complete sentence, and it should concern itself with specific actions a player may or may not take. A consequence of the rules is not itself a rule, and to avoid confusion, consequences of the rules should be covered in the Notes section, not in the Rules section.

Daphne Snowmoon wrote on 2022-05-21 UTC

This is also the same as Dobutsu Shogi's special victory conditions

H. G. Muller wrote on 2022-05-21 UTC

OK, clear. That is what I would call a delayed winning condition (like King baring in Shatranj): it only wins if it is certain you would survive the following move of the opponent. A more compact way of saying that is: " The player whose King reaches 9th rank without stepping into check first wins. "

Daphne Snowmoon wrote on 2022-05-21 UTC

At any time, the King cannot move to a square attacked by his opponent's piece. So the King should only move legally. For example, if your opponent's Rook is holding the last rank, your King cannot Campmate unless you capture that Rook or block the Rook's attack. (Because King cannot reach last rank by Rook.)

H. G. Muller wrote on 2022-05-21 UTC

You have not written that in your article, and it is not obvious. Because a King can usually 'commit suicide' when that ends the game. If I capture the opponent King, I don't have to worry whether that leaves my own King in check. If that was not the case it would be legal to step with your King next to the opponent's King when you are protected. Because he would not be allowed to capture you with that King, so you would not be in check. You cannot be in check after the game has ended. It would also be legal to step your King into the range of an enemy piece that is pinned to its own King. As that piece would not attack you, since it is pinned.

It always has to be specified explicitly whether a game-terminating condition must be fulfilled by a legal move, or whether a pseudo-legal move suffices.

Daphne Snowmoon wrote on 2022-05-21 UTC

A King cannot commit suicide. (i.e. the King cannot move to a square attacked by an opponent's piece.)

Therefore, Campmate is only established when the king is not attacked by an opponent's piece.

The player who made the Campmate first wins.

H. G. Muller wrote on 2022-05-21 UTC

You should specify whether this is an immediate winning condition (like capturing a King), or a delayed one (which could still be trumped by capturing that King on the last rank, in an 'after-move'). Or, in other words, whether the move to last rank must be legal (= avoid stepping into check). This is especially important since regular Shogi does not really have a checking rule like Chess; exposing your King to capture just loses the game, rather than qualifying as an illegal move that has to be retracted to continue the game from there.

Decimaka (revised). Game where pieces promote on making a capture. (10x10) [All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2022-05-21 UTC

I now also upgraded the general Diagram script to get more realistic piece values for this variant. It had a rather complex algorithm for determining the contribution of promotability to the piece value. Which would determine the ease of promotion based on counting the fraction of moves that would enter the promotion zone in (randomly generated) test positions, and assume the product of this ease and the promotion gain would determine the probability that this piece would indeed promote during the game. (Assuming that pieces with a less attractive promotion prospects would have to be traded away to clear the way for that.) This of course gave rather non-sensical results if there was no promotion zone at all. In that case the Diagram now assumes promotion on capture for promotable pieces (as specified by maxPromote). It then adds 50% of the promotion gain if this is positive, and subtracts 10% of the devaluation if it is a demotion (assuming there are ways to avoid it, but that this avoidance does make the piece less useful).

Pandemonium (Surajang修羅場). Capablanca chess + Crazyhouse.[All Comments] [Add Comment or Rating]
Daphne Snowmoon wrote on 2022-05-21 UTC

I added 'Campmate'.

Parahouse. (Updated!) Shogi + Strong pieces. (9x9, Cells: 81) [All Comments] [Add Comment or Rating]
Daphne Snowmoon wrote on 2022-05-21 UTC

H.G.Miller // I added Campmate. and there is still no Impasse(=Jishogi).

Campmate : The player who moved his king on the last rank wins.

ArchMage Chess. 10x10 30v30 Fantasy Chess. (10x10, Cells: 100) [All Comments] [Add Comment or Rating]
Greg Strong wrote on 2022-05-20 UTC


Now there's an interesting idea!

Daniel Zacharias wrote on 2022-05-20 UTC

The suggested changes to the summoning rule seem overly complicated to me. I would suggest instead making the summoned pieces switch sides when captured, like shogi pieces. Then the players would want to be careful about losing the demon, since that would allow the opponent to summon it later. If you want losing a summoner to be more consequential, a captured demon could only switch sides if the capturing player still has the right piece to summon it back.

Samuel Trenholme wrote on 2022-05-20 UTC

Summoning looks really overpowered, and we’re trying to figure out if we can keep the mechanic without it ruining the game.

Some ideas:

  • Summoning just puts a piece on the board once in the game, akin to Seirawan (Sharper) chess.
  • My proposal to give the other player an extra move after a summoning is done.

I mentioned Zillions, but, of course, Fairy Max might be able to implement the summoning mechanic to playtest just what compensation we need to give the other player when invoked (unrestricted extra move, restricted extra move, etc.).

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