[Retros] EQUAL LAST MOVE (ELM) - 3.06.07 Updating

[raosorio at fibertel.com.ar]

Dear friends, 

I'm posting here the ELM updated status. Wellcome to Thierry Le Gleuher and Jorge Lois.

I repeat  the complete presentation in order to make the things easier for newcomers.
We are finding that the economy is based on the most clever combination of white and
black restrictions, far away in general from a straighforward extension of previous Last Move types.

I wonder if Dead Reckoning could be useful here. 

You can send your originals via this RML or via private mail to me (many cases still pending)

Best,
Roberto

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EQUAL LAST MOVE (ELM)- Definition 
Twinning a) white to move, b) black to move. Find the a) and b) "same nature" legal last move. 

The move's nature is determined by the type of the piece/pieces involved (K, Q, R, B, N, P) and 
the type of movement (simple, straight promotion, simple capture, capturing promotion, e.p., 
pawn double step, O-O, O-O-O). 

An ELM problem is not (in general) a Last Move type D one. The diagram could present many legal 
candidates to be the last move, but there is just one for a) and just one for b) that are of 
the same nature. On the contrary, all the Last Move type DD problems are particular ELM ones. 

There are 60 theorical cases (surely 57 in practice due to castlings and e.p.)
We are trying here to find the economy records (minimal pieces number). On top of records, 
I think that this stipulation could be used to composse some nice problems with many tries. 

Some examples are a light variation of the previous Type B ones and they are indicated as such.
Dates are reception ones. 

K- (3+2=5) (8/8/8/6R1/7k/8/7K/6Rb) Bernd Schwarzkopf/9.05.2007 
KxQ (2+11=13) (8/ppppppp1/7p/7R/7K/8/7k/6nn) Bernd Schwarzkopf/9.05.2007 
KxR (3+3=6) (bK6/8/bk6/NP6/8/8/8/8) Bernd Schwarzkopf/9.05.2007 
KxB (2+3=5) (K1k5/2rp4/2P5/8/8/8/8/8 ) Bernd Schwarzkopf, Werner Keym/9.05.2007 
KxN (3+2=5) (K7/8/k7/P7/8/8/7b/6Q1) Bernd Schwarzkopf/9.05.2007 
KxP (1+5=6) (8/8/8/1q1r4/k7/n1K5/5q2/8) Bernd Schwarzkopf/9.05.2007 

Q- (8+3=11) (8/8/8/8/8/1P6/bPPPP1K1/Q1Bkq3) Bernd Schwarzkopf/9.05.2007
QxQ               PENDING
QXR               PENDING
QXB               PENDING
QxN (5+2=7) () Thierry Le Gleuher /14.05.07
QXP               PENDING

R- (5+4=9) (8/8/8/7p/4k2r/6KP/5PP1/6bR) Bernd Schwarzkopf/9.05.2007
RXQ               PENDING
RXR               PENDING
RXB               PENDING
RXB               PENDING
RXP               PENDING
 
B- (7+4=11) (8/8/1p6/b7/8/P2P4/P1kPP3/K1Bb4) Bernd Schwarzkopf/9.05.2007 
BXQ               PENDING
BXR               PENDING
BXB               PENDING
BxN (4+5=9) (2b5/3p4/8/8/8/6P1/5Pr1/3k1KBr) Bernd Schwarzkopf/9.05.2007 
BXP               PENDING

N- (5+3=8) (8/8/8/8/8/8/kPP1P3/Nbn1K3) Bernd Schwarzkopf/9.05.2007 
NxQ (3+10=13) (1nbk2NR/1p1ppppK/p6p/8/8/8/8/8) B.Schwarzkopf/9.05.2007 (Ty B,V. Bartolovic, R. Buljan) 
NXR               PENDING
NXB               PENDING
NXN               PENDING
NXP               PENDING

P- (2+2=4) (8/8/8/8/8/6P1/7p/5K1k) Roberto Osorio/20.04.2007 
P-- (3+3=6) (8/7p/7P/6pK/5k1P/8/8/8) Bernd Schwarzkopf/9.05.2007 
PxQ (3+9=12) (8/8/8/8/4N1K1/5P1P/6Pp/4BkNb) Bernd Schwarzkopf/9.05.2007 
PxR (7+2=9) (8/8/8/4KR2/7P/7P/6Pp/5BkN) Bernd Schwarzkopf/9.05.2007 
PxB (6+2=8) (8/8/8/4KN2/7P/7P/6Pp/6Nk) Bernd Schwarzkopf/9.05.2007 
PxN (5+2=7) (8/6K1/7P/8/8/7P/6Pp/6Nk) Bernd Schwarzkopf/9.05.2007 
PxP (5+2=7) (8/4K3/8/8/7P/5N1N/6Pp/7k) Bernd Schwarzkopf, Werner Keym/9.05.2007 

P-=Q (5+2=7) (7Q/8/8/7P/8/6K1/6P1/5Bkq) Bernd Schwarzkopf/9.05.2007 
P-=R (5+2=7) (7R/8/8/8/8/6P1/5K1P/5Brk) Bernd Schwarzkopf/9.05.2007 
P-=B (2+3=5) (7B/6p1/8/8/8/7K/8/6bk) Bernd Schwarzkopf/9.05.2007 
P-=N (2+4=6) (7N/8/8/8/8/8/5pr1/3k1K1n) Bernd Schwarzkopf/9.05.2007 

PxQ=Q (2+12=14) (nQr1n3/1ppKp1p1/kp1pp3/8/8/8/8/7q) Werner Keym/9.05.2007 
PxQ=R (2+12=14) (nRr1n3/1ppKp1p1/kp1pp3/8/8/8/8/7r) Werner Keym/9.05.2007 
PXQ=B               PENDING
PXQ=N               PENDING

PXR=Q               PENDING
PxR=R (7+2=9)  (7R/5K2/6P1/8/8/1P6/kP6/NrB5) Bernd Schwarzkopf/9.05.2007 
PxR=B (2+8=10) (4rnBr/5Kp1/4r3/8/81p6/2k5/b7) Jorge Lois & Roberto Osorio/2.06.07
PXR=N               PENDING

PxB=Q (2+7=9)  (5KQn/4pbn1/8/8/8/1p6/2k5/q7)   Jorge Lois & Roberto Osorio/2.06.07
PxB=R (5+2=7) (R7/2K5/1R6/8/8/P7/k7/rR6) Bernd Schwarzkopf/9.05.2007 
PxB=B (2+7=9) (5KBn/4pbn1/8/8/8/1p6/2k5/b7) Jorge Lois & Roberto Osorio/2.06.07
PXB=N               PENDING

PxN=Q (2+6=8) (KQn5/1pp5/kp6/8/8/8/8/q7) B.Schwarzkopf/9.05.2007 (Type B,many authors) 
PxN=R (4+2=6) (1R6/2K5/8/8/8/P7/k7/rR6) Bernd Schwarzkopf/9.05.2007 
PxN=B (2+7=9) (5bBn/6pK/4p3/7k/8/8/8/6nb) Jorge Lois & Roberto Osorio/2.06.07
PxN=N (2+5=7) (6KN/5r1r/6n1/8/8/8/2k5/1n6) Jorge Lois & Roberto Osorio/2.06.07