Juraj Lörinc
Rochade Europa 2010
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1.LEb7? [2.Jd5# A]
1...VAe4 a 2.Je2# B
1...LEh5 2.LEf7#
1...LEg5!
1.LEe1! [2.Je2# B]
1...VAe4 a 2.Jd5# A
1...LEh5 2.LEh4#
after the key 1.LEe1! there is one important line VAb2-c3-e5. Sc3 leaving the line deactivates it and makes e5 flight. To neutralize this effect,
the knight has to arrive at e2, activating LEe1 in the process. (The play is further complicated by Sc3 directly unguarding e4, also
re-guarded by arrival at e2. In fact, this is the main motivation of the key preparing the threat.)
Arrival of defending VA at e4 means anticipatory closing of LEe1-e5 meaning deactivation of line by 2.Se2+?
This would mean the flight e5 as there would be no hurdle left on b2-e5 and two hurdles on e1-e5.
However arrival of VA at e4 means the line LEe1-e5 is already activated! And thus, White need not care about e5 flight at all.
(Again, the complicating square e4 is blocked in this case, additional motif.) Instead, White can mate by knight at d5,
with intercepting or activating no other line.
The try is analogous. 1.LEb7? sets up the the similar situation situation with respect to the square f3 – mate 2.Sd5#
deactivates a3-f3 and activates b7-f3. 1...VAe4 closes b7-f3 in anticipation of the mate, but White can
say "Thank you for activating b7-f3 line!" and proceeds to mate at e2.
As a consequence we get le Grand theme with "complicated line motivation" (and one additional change of mates).
In this case "complicated line motivation" means both lion form of Levman defence (that is one of masked forms
of theme A) and lion form of Somov theme (theme B1, Black activates white line to a flight so that other
white line to the same flight can be deactivated). Joining together theme A and theme B is known as
Isaev theme and in the orthodox form it is quite difficult to be shown convincingly.
(This comment is a slightly edited version of extract from my Marianka 2012 lecture that explains both themes of my JT
more in detail. It should appear in the Marianka 2012 bulletin soon.)
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