AMU: Mate is possible only in the case, when mating piece is attacked by the opposite piece. If the piece is attacked twice, then it loses again the ability to give mate. (or from Juraj Lörinc’s website: Condition AMU means that the piece making the mating move must be before this mating move attacked by exactly one opposite unit.)
No.1211Gani Ganapathy &
Juraj Lörinc India / Slovakia original – 22.04.2017 For JF’s 5th anniversary
Can authors of this fine problem please explain what dual avoidance is exactly and how it applies here. It’s a phrase I sometimes see but I suspect it’s sometimes used in a looser sense. Thanks!
In the solution 1.Rg8!, the threat appears after retreating move of rook thanks to attack of bQ to Rg8.
There are two defences by bQ with different defences motifs (1…Qxg8 captures threat piece, while 1…Qb7 removes the attack of bQ from Rg8), but with the same harmful motif (both 1…Qxg8 and 1…Qb7 attack wQ). Thus seemingly there would be dual in both variations 2.Qg6# and 2.Qd7#. But there are present dual avoidance motives in both defences: 1…Qb7 additionally guards d7, preventing 2.Qd7+? by 2…Qxd7! and 1…Qxg8 additionally guards g6, preventing 2.Qg6+? by 2…Qxg6!
I have to admit that both dual avoidance and mate change themes have rather basic motivation, but the point of the composition was to show AMU-motivated play without fairy pieces in pleasant position (meredith, mirror mates). Dual avoidance is more means than aim, but it is show in my opinion in pure form.
Andrew Buchanan
April 24, 2017 01:56
Hi Juraj,
Thanks for this – very clear. But why are these defences not shown after the try 1.Qf8? There should be 1… Qxf8/Qb7 2.Rg3/Rg3.
As there is no change and both defences mentioned by you in the 1.Qf8? try do not anything to the content, they do not form any part of authors’ intention and therefore are not listed. They are there, the try is try also because it has single refutation, but need not be listed.
Actually, there is more hidden content in the position, not only what computer might show you now, but also what we have met during constructing the final position, but we have deliberately chosen to omit some content (e.g. some new checkmates, some additional defences) to have a clean position as a result.
Can authors of this fine problem please explain what dual avoidance is exactly and how it applies here. It’s a phrase I sometimes see but I suspect it’s sometimes used in a looser sense. Thanks!
In the solution 1.Rg8!, the threat appears after retreating move of rook thanks to attack of bQ to Rg8.
There are two defences by bQ with different defences motifs (1…Qxg8 captures threat piece, while 1…Qb7 removes the attack of bQ from Rg8), but with the same harmful motif (both 1…Qxg8 and 1…Qb7 attack wQ). Thus seemingly there would be dual in both variations 2.Qg6# and 2.Qd7#. But there are present dual avoidance motives in both defences: 1…Qb7 additionally guards d7, preventing 2.Qd7+? by 2…Qxd7! and 1…Qxg8 additionally guards g6, preventing 2.Qg6+? by 2…Qxg6!
I have to admit that both dual avoidance and mate change themes have rather basic motivation, but the point of the composition was to show AMU-motivated play without fairy pieces in pleasant position (meredith, mirror mates). Dual avoidance is more means than aim, but it is show in my opinion in pure form.
Hi Juraj,
Thanks for this – very clear. But why are these defences not shown after the try 1.Qf8? There should be 1… Qxf8/Qb7 2.Rg3/Rg3.
As there is no change and both defences mentioned by you in the 1.Qf8? try do not anything to the content, they do not form any part of authors’ intention and therefore are not listed. They are there, the try is try also because it has single refutation, but need not be listed.
Actually, there is more hidden content in the position, not only what computer might show you now, but also what we have met during constructing the final position, but we have deliberately chosen to omit some content (e.g. some new checkmates, some additional defences) to have a clean position as a result.