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MatPlus.Net Forum General Dual avoidance & try in helpplay problems?

### Dual avoidance & try in helpplay problems?

Could anybody, please, define the both terms in helpplay: dual avoidance and try?
Yes, yes, after publishing problems for about 7 years, I couldn't find the answer.
And the concrete examples, 2 in one day, pushed me to ask this question: www.juliasfairies.com/problems/jf-2019-ii/no-1449 & www.juliasfairies.com/problems/jf-2019-ii/no-1450. Dual avoidance or tries?

(2) Posted by Hauke Reddmann [Sunday, Sep 29, 2019 09:04]

My 50c: The terms make more sense in direct play -
White tries, Black avoids duals. Consequently, that
color scheme should also be used in help play.

Helpmates are different (© Chris Feather).
Therefore no principles inherent in direct mates should be mechanically applied to helpmates!

Hi Julia!

Below the article TRY IN HELPMATE (Encyclopedia of Chess Problems, p.441)
In a helpmate the composer may insert a try play in variety of ways: a side may seem to lack a tempo move, moves may have to be played in a correct order, etc.
Then, the composer may use a mechanism familiar from dual avoidance in direct mate problems: wrong choice of blocking unit, a pin of the mating piece, etc.

But it is not getting clearer, I guess :-)

Chris Feather ("Black To Play"):

Attempts to introduce so called "tries" have from time to time been made by a variety of composers with inspiration from directmates. The difference is that directmate tries have refutations while helpmate "tries" simply don’t work, being a failure of cooperation. While directmate tries look to Black for resourcefulness, helpmate "tries" look to the solver for incompetence!

Victoras,
how is that Feather's statement useful?
There are trivial questions and there are problems.
The answer to a trivial question could be laborious but still trivial so, there's no problem in the first place.
The solution to a problem is a principle, even if it's simple.

Some tries may be trivial and some may reveal an underlying principle.
Sequence of the moves is the answer to a stipulation.
What is relevant and what is not and why, that reveals the principle and the full solution to a problem.