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Updated version 7.0 of 10x10 chess variants (Part 1 of 2)

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Here's 10x10 computer-resistant(?) chess variant (large # legal moves + heuristics): chess pcs & the classic 6 chess variant compound pcs. Orderly setup: 1st-3rd ranks full, std chess pcs start pos kind of kept [1st update: Fools mate & kind of Scholars mate poss; links below]:

Col a Col b Col c Col d Col e Col f Col g Col h Col i Col j     Row xx

 [C]  :[A]:  [S]  :[Z]:  [M]  :[M]:  [Z]  :[S]:  [A]  :[C]:       10

:[J]:  [R]  :[N]:  [B]  :[Q]:  [K]  :[B]:  [N]  :[R]:  [J]         9

 [P]  :[P]:  [P]  :[P]:  [P]  :[P]:  [P]  :[P]:  [P]  :[P]:        8

:::::       :::::       :::::       :::::       :::::              7

      :::::       :::::       :::::       :::::       :::::        6

:::::       :::::       :::::       :::::       :::::              5

      :::::       :::::       :::::       :::::       :::::        4

:(P):  (P)  :(P):  (P)  :(P):  (P)  :(P):  (P)  :(P):  (P)         3

 (J)  :(R):  (N)  :(B):  (Q)  :(K):  (B)  :(N):  (R)  :(J):        2

:(C):  (A)  :(S):  (Z)  :(M):  (M)  :(Z):  (S)  :(A):  (C)         1

12 pc types (6 std):
Z = Amazon (mvs: N or Q), fairy pc;
C = Chancellor (mvs: N or R), fairy pc famous by Capablanca Chess;
A = Archbishop (mvs: N or B), fairy pc fam by Capa Chess;
S = Sailor (mvs: R or K), Shogi pc (promoted R or 'Dragon' in that game);
M = Missionary (mvs: B or K), pro. Shogi B (or 'Horse', in that);
J = Judge (mvs: N or K), aft fairy pc (Centaur).

Castling on 2nd rank betw K & eith R, conds as in chess. Ps act stdly; they prom on last rank to any of new pc types besides chess types. Stalemate is a draw.

1 vers of Fool's mate: 1.Pg3-g5 Pf8-f7 2.Ph3-h5 Qe9-i5 mate; 1 vers of Scholar's mate: 1.Pf3-f5 Pf8-f6 2.Bg2-d5 Nc9-d7 3.Qe2-g4 Nd7-e5 4.Qg4xg8 mate.

This variant I dub 'Sac Chess' (see initials of last 3 pcs on White's 1st rank); if one avoids blund'ing early, a typ game may go a while: many pcs & sqs, & a K may typ'ly be well defended a while. Howev advocates of Go say chess is a battle (40 moves/side avg), & Go is a war (75 moves/side avg).

[2nd update: On avg 2 units traded in chess per 10 ply. Avg game 80 ply, leaving 16 units on avg. To leave 16 units Sac Chess at worst avg 8 ply x 22 units traded = 176 ply (or 88 moves). Hyp Sac Chess TC: 40 moves/1.5 hrs., 30/1, adjourn, 30/1, adjourn if nec, OR Game/90 + 30 sec incr as std for chess]

Below's a link to free package to play variants, e.g. Sac Chess:

1st link below: 1st Sac Chess game (mate in 36), then 2nd to rest; 3rd: a page on free membership site that includes the ability for its members to play 100s of variants vs. each other by email free (on boards of various shapes & sizes; diagrams shown), e.g. Sac Chess, & its members can post comments or email each other (addresses protected vs. bots):]

For any thinking Sac Chess too complic to get pop'ty, below's link re: more com'x Middle Shogi variant (to std. 9x9 Shogi, or Japanese chess); still has fans.

In Sac Chess poss point underpromoting to other pc than amazon, but point may be mate sooner or get most val underpromoted pc, based on pos I've imagined. Smothered or back rank mates conceivable, but they'd be rarer than in chess (Grand Chess'd have similar arguable drawback); note amazon (or archbishop with K in corner) can deliver mate by itself, which alone may not make Sac Chess a draw with perfect play.

Here's link re: 'Grand Chess':

Physical 10x10 boards in use, e.g. search "10x10 Draughts" on; there are some sellers of physical fairy chess pcs; ones can be made, e.g. using elastics around extra chess set(s') pcs, or even coins.

A name at least some might prefer instead of 'Sac Chess' (if ever popular) might be 'International Chess'.

A possible variant on 'Sac Chess' (for any not liking Zs being clearly superior to Qs in terms of legal moves relatively poss): replace all 4 Zs as follows:
(1) on the 'd' file replace the amazons for each side with a new type of pc that combines the powers of R, N & K, & I call it a 'Ship' or 'H';
(2) Replace the amazons on the 'g' file with a new type of pc that combines the powers of B, N & K, & I call it a 'Freemason' or 'F'. Note in the new start position like for chess, more vers of Scholar's mate'd be poss than in 'Sac Chess'.
Based on what the initials of the 1st 4 pcs on White's 1st rank'd be, I'd dub this variant 'Cash Chess'. I prefer using amazons, with more symmetry in start position & 1 less pc type used.

[edit: or, for 'Royal Bevy Chess', replace amazons with queens, and the queen with an amazon]

[3rd update: another poss variant I'd dub 'Royal Sac Chess': in case of stalemate or 3-fold repetition of moves (a claimed perpetual check being 1 case of this), a player wins if he has more queens (Q) left on the board than his opponent, otherwise the result is a draw. Thus queens would get 1 little distinction over amazons.]

Here's a sample Sac Chess opening possibility, besides the Fool's mate & Scholar's mate given earlier. It starts in a way like the Italian, Two Knights Defence, Wilkes Barre variation in chess:

1.Pf3-f5 Pf8-f6 2.Nh2-g4 Nc9-d7 3.Bg2-d5 Nh9-g7 4.Ng4-h6 Bg9-d6 5.Bxg8+ Ai10xg8 6.Nh6xg8 Zg10xg8.

In my estimation Black has adequate compensation for his archbishop based on his lead in development. Here's the position after Black's 6th move:

Col a Col b Col c Col d Col e Col f Col g Col h Col i Col j     Row xx

 [C]  :[A]:  [S]  :[Z]:  [M]  :[M]:       :[S]:       :[C]:       10

:[J]:  [R]  :::::  [B]  :[Q]:  [K]  :::::       :[R]:  [J]         9

 [P]  :[P]:  [P]  :[P]:  [P]  :::::  [Z]  :[P]:  [P]  :[P]:        8

:::::       :::::  [N]  :::::       :[N]:       :::::              7

      :::::       :[B]:       :[P]:       :::::       :::::        6

:::::       :::::       :::::  (P)  :::::       :::::              5

      :::::       :::::       :::::       :::::       :::::        4

:(P):  (P)  :(P):  (P)  :(P):       :(P):  (P)  :(P):  (P)         3

 (J)  :(R):  (N)  :(B):  (Q)  :(K):       :::::  (R)  :(J):        2

:(C):  (A)  :(S):  (Z)  :(M):  (M)  :(Z):  (S)  :(A):  (C)         1

Now best may be 7.Pe3-e4 Pe8-e6 8.Pi3-i4 (to stop ...Bd9-h5). Black can win back his pawn, but White can castle.

Here's my tentative estimates for the relative values of Sac Chess pcs:

P=1, N=3, B=3.5, R=5.5, Q=10, almost as in chess (note a 10x10 board increases the scope of the long-range pcs). My estimates for the new pcs in Sac Chess are:

Z=14 (just as Q=R+B+P in value, Z=Q+N+P in value)
C=9.5 (just as Q=R+B+P in value, C=R+N+P in value)
A=7.5 (just as Q=R+B+P in value, A=N+B+P in value)

Also, I recall that a chess K has a fighting value of 4 (even though it cannot be exchanged); this value in my view might be rather oddly expressed (for lack of a known formula) as
chess K = 32 x (max. # cells chess K moves to [eight])
divided by
(# of cells on a chess board [sixty-four])
= 4;

similarly, a Sac Chess K has a fighting value of
32 x (max. # cells Sac Chess K moves to [eight])
divided by
(# of cells on Sac Chess board [one hundred])
= 2.5 approx.

S=7.25 (only half a king's moves are added to a rook to make a sailor, & since Q=R+B+P in value, so S=R+(K/2-P/2)+P in value)
M=5.25 (only half a king's moves are added to a bishop to make a missionary, & since Q=R+B+P in value, so M=B+(K/2-P/2)+P in value)
J=6.5 (just as Q=R+B+P in value, J=N+K+P in value).

For those wishing to replace Zs with the 2 other pcs I suggested earlier, I estimate their relative value as follows:

H (Ship) = 11.25 (just as Q=R+B+P in value, H=S+N+P in value)
F (Freemason) = 9.25 (only half a king's moves are added to an archbishop to make a freemason, & since Q=R+B+P in value, so F=A+(K/2-P/2)+P in value).

While I estimate a ship'd be worth more relative to a queen, at least a queen's pwrs are not duplicated (and then some) by it. I should also mention I've imagined cases where it's advantageous in some way to promote to a freemason (or ship).

Below is a link to Part 2, re: 10x10 Crazyhouse/Bughouse ideas of mine:

[4th update: 4 links below mention Sac Chess]

[5th & 6th updates: Below's link to Alekhine Chess: 56 pc 14x8 variant, has some fans; for space/aesthetic reasons alone, I prefer a sq 10x10 board]

Updated 08-11-2018 at 12:35 AM by Kevin Pacey

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Chess variants