# [Retros] EQUAL LAST MOVE (ELM) - 26.06.07 updating

raosorio at fibertel.com.ar raosorio at fibertel.com.ar
Tue Jun 26 19:09:02 EDT 2007

Dear friends,

I'm posting here the ELM updated status.

I repeat the complete presentation in order to make the things easier for newcomers.

Bernd and Werner have hardly worked to compose the pending cases (assuming that just 57
are posible. I still have some doubts about the e.p. one based on Dead Reckoning).

ELM has been presented by Werner Keym in the Die Schwalbe june issue. In the same issue
Bernd Schwarzkopf published in the original section an improvement of NxQ using 11 pieces.
This was an improvement on the previous record but last week Bernd and Werner produced a
7 pieces example for this case. Even 4 pieces less! This fact is clearly showing that we
are developing the first learning period to discover the intrinsic ELM potential.

Many of the present records are waiting for impovements.

You may send your originals via this RML or via private mail to me.

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, i) means improved from previous updating, and n) means new.

I included the reference of the Last Move Type DD record (Type DD is the particular Type D cases
where the last move is of the same nature both for WTM and BTM) in the form of DDxx, where xx
is the number of pieces in the corresponding DD record.

For instance, in the following first case the move is K-, after that DD12 indicates that the DD
record uses 12 pieces, and after that (3+2=5) means that the ElM record uses 3 white pieces
and 2 black pieces, total 5. Then, the FEN, author and reception date.

K- DD12 (3+2=5) (8/8/8/6R1/7k/8/7K/6Rb) Bernd Schwarzkopf/9.05.2007
KxQ DD24 (1+11=12)(3nK2k/ppppp2p/4p2n/7p/8/8/8/8) Bernd Schwarzkopf/14.06.2007
KxR DD22 (3+3=6) (bK6/8/bk6/NP6/8/8/8/8) Bernd Schwarzkopf/9.05.2007
KxB DD14 (2+3=5) (K1k5/2rp4/2P5/8/8/8/8/8 ) Bernd Schwarzkopf, Werner Keym/9.05.2007
KxN DD10 (3+2=5) (K7/8/k7/P7/8/8/7b/6Q1) Bernd Schwarzkopf/9.05.2007
KxP DD24 (1+5=6) (8/8/8/1q1r4/k7/n1K5/5q2/8) Bernd Schwarzkopf/9.05.2007

Q-DD13 (5+4=9) (8/8/8/3k4/8/PP6/qnpP4/1QK5) Bernd Schwarzkopf/08.06.2007
n)QxQ DD?? (9+3=12) (8/8/8/8/8/4P1PP/1K1kPBPq/3N1Q1b) Bernd Schwarzkopf 22.06.2007
n)QxR DD?? (7+2=9) (8/8/8/8/1N6/kPP5/q1PP4/1QK5) Bernd Schwarzkopf/21.06.2007
n)QxB DD?? (7+3=10) (8/8/8/8/8/PK2B3/1pN1R3/QRqk4) Bernd Schwarzkopf 21.06.2007
QxN DD12 (5+2=7) (8/8/8/8/8/P7/1PP5/qQK1k3) Thierry Le Gleuher /14.05.07
n)QxP DD26 (9+2=11) (4K2B/7k/7N/6RQ/5N1q/5PPP/8/8) Werner Keym/21.06.2007

R- DD13 (5+3=8) (8/8/8/8/1p6/P7/rPP1k3/1RK5) Bernd Schwarzkopf/08.06.2007
n)RxQ DD17 (10+3=13) (8/8/8/8/8/P1P5/rP1PPPPP/kr1RK3) Bernd Schwarzkopf, Werner Keym/21.06.2007
i)RxR DD?? (8+2=10) (8/8/8/8/BPK5/1R1P4/LNk5/r1B5) Bernd Schwarzkopf, Roberto Osorio, Jorge Lois/21.06.2007
RXB DD18 (4+4=8) (8/8/8/8/1p6/p7/rPP1k3/1RK5) Bernd Schwarzkopf/08.06.2007
RXN DD9 (3+4=7) (8/8/8/8/8/np6/rP2k3/1RK5) Bernd Schwarzkopf/08.06.2007
n)RxP DD25 (6+2=8) (8/8/4K3/8/7P/4N1NR/5Pr1/6k1) Werner Keym/21.06.2007

B- DD12 (7+4=11) (8/8/1p6/b7/8/P2P4/P1kPP3/K1Bb4) Bernd Schwarzkopf/9.05.2007
n)BxQ DD24 (9+2=11) (8/8/6P1/4PPP1/7B/5P1P/5KPb/7k) Werner Keym/21.06.2007
n)BxR DD11 (2+6=8) (5b1B/4pK1k/5ppp/8/8/8/8/8) Bernd Schwarzkopf/21.06.2007
n)BxB DD27 (6+4=10) (4RBkb/3Pp2p/4KPP1/8/8/8/8/8) Bernd Schwarzkopf, Werner Keym/21.06.2007
BxN DD11 (6+2=8) (8/8/8/8/8/4P1PP/5BPb/4K2k) Bernd Schwarzkopf/06.06.2007
n)BxP DD26 (8+3=11) (8/8/6P1/6P1/3K1P1B/7N/5PPb/6nk) Werner Keym/21.06.2007

N- DD11 (5+2=7) (8/8/8/8/8/5K2/4PPPk/6Nn) Bernd Schwarzkopf/08.06.2007
i)NxQ DD17 (3+4=7) 6Nk/4p1Rn/4K2p/8/8/8/8/8 Bernd Schwarzkopf, Werner Keym/24.06.07
n)NxR DD16 (3+5=8) 5BNk/4pK1n/7p/6p1/8/8/8/8 Bernd Schwarzkopf /23.06.2007
NXB DD19 (2+7=9) (5KNr/4p1np/4q3/5k1b/8/8/8/8) Roberto Osorio & Jorge Lois/9.06.07
NXN DD17 (5+3=8) (8/8/8/8/7P/4K1kP/6Pn/6Nb) Bernd Schwarzkopf/12.06.2007
n)NxP DD25 (8+3=11) (8/8/6P1/5PP1/6PN/6Kp/6Pn/6Bk) B.Schwarzkopf, Werner Keym/21.06.2007

P- DD8 (2+2=4) (8/8/8/8/8/6P1/7p/5K1k) Roberto Osorio/20.04.2007
P-- DD17 ( 3+3=6) (8/7p/7P/6pK/5k1P/8/8/8) Bernd Schwarzkopf/9.05.2007
PxQ DD24 (3+7=10) (8/8/8/8/4N1K1/5P1P/6Pp/4BkNb) Bernd Schwarzkopf/9.05.2007
PxR DD21 (7+2=9) (8/8/8/4KR2/7P/7P/6Pp/5BkN) Bernd Schwarzkopf/9.05.2007
PxB DD16 (6+2=8) (8/8/8/4KN2/7P/7P/6Pp/6Nk) Bernd Schwarzkopf/9.05.2007
PxN DD16 (5+2=7) (8/6K1/7P/8/8/7P/6Pp/6Nk) Bernd Schwarzkopf/9.05.2007
PxP DD18 (5+2=7) (8/4K3/8/8/7P/5N1N/6Pp/7k) Bernd Schwarzkopf, Werner Keym/9.05.2007

P-=Q DD20 (5+2=7) (7Q/8/8/7P/8/6K1/6P1/5Bkq) Bernd Schwarzkopf/9.05.2007
P-=R DD20 (5+2=7) (7R/8/8/8/8/6P1/5K1P/5Brk) Bernd Schwarzkopf/9.05.2007
P-=B DD10 (2+3=5) (7B/6p1/8/8/8/7K/8/6bk) Bernd Schwarzkopf/9.05.2007
P-=N DD16 (2+4=6) (7N/8/8/8/8/8/5pr1/3k1K1n) Bernd Schwarzkopf/9.05.2007

PxQ=Q DD24 (2+12=14) (nQr1n3/1ppKp1p1/kp1pp3/8/8/8/8/7q) Werner Keym/9.05.2007
PxQ=R DD23 (2+12=14) (5+6=11) (6R1/4Kpp1/5ppN/8/8/8/1R6/krN5)Bernd Schwarzkopf/12.06.2007
n)PxQ=B DD25 (2+11=13) (2b1B3/pp1pp1p1/6p1/8/8/1k6/2rp4/bK6) Werner Keym/21.06.2007
n)PxQ=N DD24 (2+10=12) (2b2Nr1/1p1p1ppK/4p1p1/8/8/8/7k/6n1) Werner Keym/21.06.2007

PXR=Q DD?? (3+6=9) (4rnQ1/5Kp1/8/8/8/5P1k/4r3/6q1)Jorge Lois & Roberto Osorio/14.06.07
PxR=R DD20 (7+2=9) (7R/5K2/6P1/8/8/1P6/kP6/NrB5) Bernd Schwarzkopf/9.05.2007
PxR=B DD24 (2+8=10) (4rnBr/5Kp1/4r3/8/81p6/2k5/b7) Jorge Lois & Roberto Osorio/2.06.07
n)PxR=N DD24 (3+6=9) (5bNN/6pK/6p1/8/8/6p1/5k2/7n) Bernd Schwarzkopf/22.06.2007

PxB=Q DD26 (2+6=8) (5nQK/5pr1/8/8/8/1p6/2k5/q7) Jorge Lois & Roberto Osorio/14.06.07
PxB=R DD16 (5+2=7) (R7/2K5/1R6/8/8/P7/k7/rR6) Bernd Schwarzkopf/9.05.2007
PxB=B DD25 (2+6=8) (5nBK/5pr1/8/8/8/1p6/2k5/b7)Jorge Lois,Roberto Osorio & Werner Keym/23.06.07
PXB=N DD16 (4+3=7) (7N/5K1k/6R1/6Q1/8/8/8/6bn) Roberto Osorio & Jorge Lois/16.06.07

PxN=Q DD23 (5+2=7) (5nQK/5pr1/8/8/8/8/2k5/1q6) Roberto Osorio & Jorge Lois/16.06.07
PxN=R DD14 (4+2=6) (1R6/2K5/8/8/8/P7/k7/rR6) Bernd Schwarzkopf/9.05.2007
PxN=B DD24 (2+7=9) (5bBn/6pK/4p3/7k/8/8/8/6nb) Jorge Lois & Roberto Osorio/2.06.07
PxN=N DD22 (2+5=7) (6KN/5r1r/6n1/8/8/8/2k5/1n6) Jorge Lois & Roberto Osorio/2.06.07