Comments/Ratings for a Single Item

There will be a ZRF posted.  Until it's on the CV pages, I will send a
copy by email to anyone who requests it.

I think my playing tip about not using the pocket just to mutate a piece
might well be extended to promotion as well -- don't aim for promotion as
your sole objective -- try to gain a material or positional advantage in
addition.

The kind of pawn promotion I like is dropping a pawn on the seventh rank
to fork two pieces and threaten to make a Bishop or Knight.

In general, moves with multiple objectives will be even more frequent than
in FIDE Chess.

Astute readers will notice that the value classes are based on Ralph
Betza's Atomic Thoery of Piece Values.  The equivalances are not exact --
a SuperBishop is measurably stronger than a Rook, but the difference is
small enough (half a pawn, maybe) that positional factors can easily
override it.

If anyone does want an alternate piece set, I would suggest a coherent
set based on a small number of elements.  My piece set is based on three
pieces (Knight, Bishop, Rook) and their combinations plus three
enhancements (change Knight to Nightrider, add Wazir to Bishop, add Ferz
to Rook).

Some thoughts on the pieces:

The pawn is about the same value as in FIDE Chess: while it can only
promote to Bishop, it promotes to a Bishop that is itself promotable.

I don't expect to see an AmazonRider in an actual well-played game, but I
just had to have it for logical completeness. I wonder if an AmazonRider
is really all that more powerful than an Amazon on an 8x8 board: the
difference certainly feels less than the gap between Knight and
Nightrider.

The SuperChancellor can mate unassisted--the only value class 6 piece
which can do so.

The leveling effect among pieces of the same value class is stronger than
in other chess variants, since by spending a tempo, you can mutate one
into another. On the other hand, among pieces in the same value class
their are slight differnces in value based on the type of position.  In
open/wide open positions, the most valuable move components seem to be
Rook, Bishop, Knight in order and Wazir or Ferz is a more valuable
enhancement than Nightrider.  In closed/severly closed positions, the
reverse is true.  In-between positons seem to favor Bishops.

This is an excellent game! The pocket allows for many surprises.
I played its zrf many times and I found a very small error in it. The
piece CancellorRider is missing its one step diagonal move.

Daniel,

Thank you for finding the bug in the ZRF (it actaully affected the
SuperChancellorRider).  I have subbitted a corrected zrf to the CV pages.

I'm presently losing my game of Pocket Mutation Chess against Peter
Aronson in Invent-and-Play Section 2, and it is obviously a very enjoyable game.
I blew up my position at move 5:

1. Rook h1 - WP = Nightrider
1. Pawn d7 - d5
2. Nightrider WP - f4
2. Queen d8 - BP = CardinalRider
3. Rook a1 - WP = SuperBishop
3. Pawn g7 - g6
4. SuperBishop WP - e5
4. Knight g8 - f6
5. SuperBishop e5 x c7 ??
5. CardinalRider BP - g5
6. Knight g1 - f3
6. CardinalRider g5 x c7...

Despite this outcome, I am afraid that the sole advantage of being White
was bound to give me a quick win. (Peter is not so sure.) The Nightrider
can be dropped on c4, threatening King and Rook, or f4, threatening Queen
and Rook. It is forking a fork, so to say.
So, I think that White should be barred from using the Pocket at his
first move. (Peter agrees with me on this.)

Antoine raises a good point.  Consider it done. Rule 2 is amended to read:
'If a player's pocket is empty, the player may remove any of his pieces
(except his King) from the board and put it in his pocket as a move. White
may not use the pocket for the first move.'

I will also submit a corrected ZRF when I am able.

I hav submitted the corrections to the editors. It is a good change in that
reducing White's opening advantage is always a good thing.

However, the original rules do not give White a win.  Black can maintain
equality by symmetrical play. The early loss of one Rook on each side is a
bit of a flaw, though.

In the revised rules, White is safe from the Nightrider attack if he opens
Pawn d2-d4 or Pawn e2-e4. This covers one fork point and he has the tempo
to cover the other if Black mutates a Rook to Nightrider.  Since these are
reasonable opening moves anyway, diffusing the Nightrider threat costs
White little or nothing--this makes for a very balanced game.

Is mutuation when pocketing a piece from the eighth rank optional or
mandatory?  For example, White pockets a KnightRider from a8 -- does he
have the option of retaining a KnightRider or is he forced to 'upgrade'
to a Cardinal or SuperRook.  White may find the NR ability too useful to
give up.

What if you added a new Piece, the 'SuperKnightRider', or 'KingRider',
which moves as King or KnightRider?  Would this be approximately the right
strength for a Class 4 Piece?  If you think it is too strong, perhaps a
FerzRider or WazirRider would be better.

Promotion via mutation is mandatory when pocketing a piece on the eight
rank, excepting the case of the AmazonRider which can be pocketed form
the
eighth rank without promoting since there is no higher rank for it to
promote to. A variant you where promotion is optional also has a great
deal of merit.

Your proposed SuperNightRider would be value class 5.  A Nightrider-Ferz
or Nightrider-Wazir would be class 4, as would a SuperKnight.

Carlos, 

Yes and No.

FIDE Chess rules apply to Pocket Mutation Chessexcept where otherwise
stated.

Under current FIDE rules, perpetual check is not a draw in and of itself
(it once was), but if you are able to give perpetual check, you can always
force triple repetition or the 50-move rule, both of which are draws. 

Note that Pocket Mutation's 50-move rule is different from FIDE:
promotions and captures reset the move count, but Pawn moves do not.

1. P b2-b3 
1... p d7-d5 
2. R a1-p1; I-p1 // pocket nightrider 
2... b c8-d7 
3. I p1-b2 //  is a PMChess Fool's Mate.  Neat!

This variant has the potential to go beyond excellent. Bringing Class 4 up to four pieces yields 21 different pieces for the game, including the King. And 21, being the product of the magic numbers 3 and 7, makes a traditional choice for a complete set. I suggest adding the SuperAlibaba to Class 4, as its WFAD moves make a nice change from long range pieces.

I have an idea for Pocket Mutation Demotion Chessgi. It will use the same
pieces and value classes as PM. 

The rules for using the pocket are expanded:

When you capture an enemy pawn, it is removed from the game. If you
capture any other enemy piece, it is demoted to the next lower value
class, mutated to a friendly piece of your choice in that class, and put
in your pocket. This is mandatory even if your pocket is not empty and
will cause the removal of any piece in your pocket from the game. 

Notice how you can't put a strong piece in the pocket and wait around for
a good drop--in effect you can only capture pawns as long a s that strong
piece is there.

Imagine having a Queen in your Pocket and the opponent checks with a
Knight and the only counter is to capture the Knight. At the cost of a
Knight, the enemy has changed your Queen into a pawn!

This is a very interesting game. I look forward to playing it in GCT #2.

Below is a list of mobility values for all the pieces in Pocket Mutation, as well as a few Chess-With-Different-Armies pieces at the bottom for comparison. The 'average mobility' column is a Betza Mobility Calculation with a magic number of 0.7. This is probably the best estimation of the value of the piece. The second column is the average number of checks this piece delivers on an empty board without being counter-attacked. The third column is the average number of different 'directions' in which this piece attacks. The fourth column is the average number of squares attacked on an empty board.