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MatPlus.Net Forum Twomovers Pas de deux

### Pas de deux

Inspired by a MP posting ("Mirror Moves"), I quickly composed the
following 2#. (It's substandard but I only wanted to show the theme.)

(= 7+3 )

Only the thema variants (go find everything else alone, including solution :-) :
1.Sa8? Sa4!, 1.Se8? Se4!, 1.Sa6? Sxa6!, 1.Se6? Sxe6!

I also composed a lot of examples with parallel moving on the occasion
of Loshinsky's 100th, and will make a little article (maybe for his
111th? :-). I feel that this problem could be thrown in for good measure,
and obviously a third possibility (i.e. white and black pieces move in
the opposite direction) is still unresearched. Also note that in this
problem Black mimics White, while in the Loshinsky-inspired ones it's
the other way round.

So: Whoever wants to jump in here, will be included in the article.
Only thematic requirement:
1a Whites mate mimics Blacks defense or
1b Blacks parry mimics Whites try, and "mimic" is
2a Same vector or
2b Mirrored vector or
2c 180° Rotated vector
(or 2d free rotated vector, if your muse is a troll :-)
(This problem: 1b2b.)

Show *at least* 2 variants lest the solver will probably find it
artificial otherwise.

EDIT: In the article, only orthodox 2#. What you add here is

Hauke

Have another one, composed on the fly during the (club) Lübeck
solving competition (you know me, I'm read in half the time :-)
Type: 1a2c.

(= 7+7 )

1.Sf6! (2.Th7) Be5/Be3 2.Bg3/Bg5

I don't know what keeps you from adding, I compose an example
in five minutes (it has to be just an example after all,
I don't want to take away a Loshinsky-like masterpiece from you :-)

(= 8+7 )

1.f8Q (Fleck) Qc3/Qc4/Qc5 2.Qf6/Qf5/Qf4

1a2c, illustrating mainly what you should NOT do, under any circumstances:
let concurrent parades like Qxb2 or Bc3 interfere with the solver
recognizing the intended theme.

A related idea:

G.W.Chandler
Op de Hoogte 1913

(= 11+8 )

Mate in 2

1.Qh8 (>2.Qh4)
1...Rd3 2.Rf5
1...Re3 2.Rf4
1...Rxf3 2.Rxf3

(1...Rcb3 2.Rxc4
1...Sc5 2.Rd6
1...Sxg6 2.Qd8)

Neato. Falls under my description (EDIT: 1a2d, 90°) and will definitely be
included. (I personally avoid unrelated byplay and would
move everything "against the wall" to save a few pieces [8+8],
but that is stuff for endless discussion :-)

Here is a simple one with three different motivations.

(= 5+3 )

Key: 1. Kxd7 [2. Bxh7#]
1... Bg6 2. Bf7#
1... Bf5+ 2. Be6#
1... Be4 2. Bd5#
(1... Bxg8 2. Rxg8)

I suppose that another variation can be easily added with a different (but inferior key

A task featuring the theme 7 times using queens:
http://www.yacpdb.org/#1271

Four thematic variations in a nice mutate by Ahues, though with only two motivations.

Herbert Ahues
5th Prize, Chess 1956

(= 7+8 )

Mate in 2

Set 1...B~ 2.Rxg6

1.Bxg6

C.Goldschmeding
(= 10+11 )
#2

THX for the additions. Obviously, there
is a ton of rook-rook-duels in the n# genre, and
"duel" in the 2# Albrecht database alone lists 580 entries.
Still much research to do :-) Random example:
(= 12+11 )

S. Shedej, Sportivna Gaseta 1990

@Arpad: I can't count the Bakcsi problem,
since the vectors are not always equal
(otherwise any "duel" would qualify).

@Darko: This seems to be a slightly economized
version with respect to the one in the Albrecht database.

@Seetharaman and Daniel: Indeed.
(= 6+5 )

Since the Ahues one is far superior, just added
to answer the question (yes, 3 motivations work).

Heres one for 1b2a by Klemanic: http://www.yacpdb.org/#244143

I tried my best to make it four RR oppositions (I had to slap
a sucking solution on it in return), but the matrix is fighting back.
Can you do it better?

(= 8+10 )

1.Rb4/c4/e4/f4? Rb3/c3/e3/f3! (1.Qa6!)

If you forgo the flight giving key and have a key like 1.Kb6 threat 2.Qc7 you get an almost dual free version.

With only 3 tries but with black and white correction :

Colin Sydenham
Diagrammes 1980
(= 8+5 )
2#

1.Rg8? [2.B×e7‡]
but 1…Re8!

1.Rg5!? [2.B×e7‡]
but 1…Re5!

1.Rg4!? [2.B×e7‡]
but 1…R×e4!

1.R×g3! [2.B×e7‡]
1…R~ 2.R(×)e6‡
1…Re8 2.Bg7‡
1…Re5!? 2.f×e5‡
1…R×e4!? 2.Sc×e4‡