[Retros] DR vs forced ep: what rule predominates?

liskov at im.bas-net.by liskov at im.bas-net.by
Mon Aug 27 20:07:40 EDT 2007

Dear Andrew and retro-friends,

In the current FIDE Laws of Chess 2004/05 a (minor) collision seems
to exist between "Dead Reckoning" (Art.5.6b and 9.6) and the rule
concerning e.p. capture (Art.3.7d). Let me recall the last sentence
in the latter (I wrote much about it in April), which says that
e.p. "MUST be made in the event that no other legal move is
possible" (capitalized by me). At the same time, the former stops
a game immediately whenever such a forced e.p. results in an
inavoidable stalemate ("if the position is such that neither player
can possibly checkmate, the game is IMMEDIATELY drawn").

It is not a difficult matter to compose a special problem that puts
both rules into conflict. To make the collision more spectacular I
offer the following twins:


| _ : _ : B : _ :|

| : _ : _ : _ : _|

| _ : r : _ : _ :|

| p _ : _ : _ : _|

| k p _ : _ p _ :|

| s R : P P p : _|

| _ : P K p S _ :|

| R Q B _ S _ : _|


(a) Diagram. =1.
(b) -wPe3. =in [minimally] how many single moves?

(a) 1.c4 =! A draw by DR (Art.5.6b): an inavoidable stalemate
after 1... bxc3 e.p.+ 2.Rxc3 fxe3+ 3.Kxe3= OR at once 1... fxe3+
2.Kxe3=. The last sentence of Art.3.7d is not applicable here.

(b) Two different solutions are possible.
I. If again we are guided at once by DR, then the answer is:
IN 1 SINGLE MOVE. As above, 1.c4 =!. Game IS OVER (as the
possible SUBSEQUENT game shows), and Art.3.7d (last sent.)
plays no role already.

II. If we are (first) guided by the last sentence of Art.3.7d
(whose applicability here is STRAIGHTFORWARD), then this forced
e.p. capture is COMPULSORY, and the answer is different:
IN 2 SINGLE MOVES! Only after e.p. may and should we apply DR:
1.c4 bxc3 e.p.+(!) =.

A contradiction. I see no FORMAL arguments allowing to legally
exclude I or II and to prefer the other. The rules have EQUAL
rights, and any rule could have been reformulated explicitly so as
to be subordinate to the opposite rule: "Claim A, unless Claim B
is applicable"... It is insufficient to appeal to common sense.
IMHO, a correction is needed.

What do you think?
Valery Liskovets

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