The zugzwang is a big theme in studies, and AJR used to publish lists of zugs - often in EG. Unfortunately, these lists were often found to have errors.
for the complete list of value-critical ('Type A') zugs.
See http://centaur.reading.ac.uk/view/creat ... 00763.html
and specifically http://centaur.reading.ac.uk/4518/
for definitions and examples of Type B and Type C zugzwangs - and an explanation of why the term 'reciprocal zugzwang' is not 100.000% apposite!
I would like to have examples of studies which anyone thinks have been over-assisted by EGTs, and examples of judges who thought so.
A fundamental problem in the studies community is that judges appear to have very different criteria, all of which are 'secret'. A better way forward might be that each judge declares a one-page manifesto on their judging stance.
John Nunn has written most clearly on the issues around studies and EGTs, and I agree with his perspective. The means of composition is irrelevant: it is the output that is being judged. Perhaps the confusions between 'process' and 'output' is confused by the fact that the word 'composition' describes both.
There is another instrinsic problem. There are certainly studies which are proved by EGTs to have an absolutely unique solution - not even a single 'ignorable dual' - but which have too long a solution for human consumption. It may be because of this that they are deemed not to have artistic merit, or maybe they did not have artistic merit anyway.
'Length' is not the only technical parameter testing human understanding. 'Width' is another. If a thicket of side-variations have to be explained away, the explanation of the solution becomes indigestible. The composer needs to explain away not only alternative moves for White which meet the goal but moves which appear to meet the goal but in fact do not.
On the other side of the study/EGT problem scenario, I found AJR's arguments, effectively against studies now going into 'EGT territory', to be too aggressive: at times they degenerated into goal-based rhetoric. I was reminded of the Stalinistic logic that sent more than one Russian study composer to the gulag because their compositions were not accessible enough to 'the people'.
I challenged AJR to produce an 'EGT study' based on casually picking up a position from an EGT and turning it into a study: he hasn't done so and I don't believe he would find it easy.
AJR's stance caused a most unfortunate hiatus in the judging of the Bent Memorial Tournament, when the other two judges did not agree with his stance on studies going into 6-man territory. All of this subtracts from AJR's reputation which is a pity as he has given much to the world of the chess study.