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MatPlus.Net Forum General Questions with terminology
 
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(1) Posted by Mu-Tsun Tsai [Saturday, Jul 29, 2023 15:40]

Questions with terminology


1. If the key of a problem gives virtual threat(s), is the problem still considered a threat problem, or a block problem actually, or something in between?
2. Why is “set play” so called? I mean, what does “set” mean in this context?
 
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(2) Posted by seetharaman kalyan [Saturday, Jul 29, 2023 16:51]

Setplay means of course the play already 'set' in the diagram position
 
 
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(3) Posted by Mu-Tsun Tsai [Sunday, Jul 30, 2023 06:30]

I see. That makes sense.
 
   
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(4) Posted by Hauke Reddmann [Sunday, Jul 30, 2023 19:26]

"Block Threat" exists as description.
https://kmoen.people.ua.edu/by-play-blog/block-threat
 
   
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(5) Posted by Frank Richter [Sunday, Jul 30, 2023 20:07]

What exactly do you mean with "virtual threat(s)"? Threats, that are im German called "unausführbar" ("unfeasible")?
 
   
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(6) Posted by Joost de Heer [Sunday, Jul 30, 2023 20:48]

Virtual threat is probably a threat which every black move defends against.
 
   
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(7) Posted by Michael McDowell [Monday, Jul 31, 2023 10:19]

I presumed that virtual threats meant unforced threats. They are a constituent part of the Ojanen theme, such as this very cute wK6.

Stanislav Kirillov
Vestnik Problemista 1992

(= 4+3 )

Mate in 2

1.Bb2 (2.Kb4, Kc4, Kd2)
1...Sb3/Sc2/e3 2.Kxb3/Kxc2/Kd3

I would class a problem with virtual threats as a threat problem, as "block" implies no threat.
 
   
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(8) Posted by Frank Richter [Monday, Jul 31, 2023 10:37]

(deleted)
 
   
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(9) Posted by Mu-Tsun Tsai [Tuesday, Aug 1, 2023 01:12]

What I mean by virtual threat is, to borrow the definition from the Encyclopedia of Chess Problems, "a threat that does not materialize against any black move, i.e. the post-key position is a zugzwang as well". Basically the same as what you guys said.

Since someone mentioned block-threat, that also confused me as well. Since the problem is actually solved by a threat, why is still categorized as a block problem (at least by the said book)? This kinda contradict the very definition of a block problem, isn't it?
 
   
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(10) Posted by Joose Norri [Tuesday, Aug 1, 2023 03:12]

In a block-threat the position is a complete block before the key, not after; the key introduces a threat.
 
   
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(11) Posted by Mu-Tsun Tsai [Tuesday, Aug 1, 2023 03:59]

Yes I agree, so as a position it is block, but as a problem, wouldn't it make more sense to say that it is "a threat problem disguised as a block problem" instead?
 
   
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(12) Posted by Kevin Begley [Tuesday, Aug 1, 2023 04:55]

This is a difference without distinction.

A blocked problem provides all legal replies.
A threat problem provides all legal replies which prevent the threat.
A problem with virtual threats lies at the center of the Venn diagram.

It is mildly interesting that none of threats can occur in a certain class of problems, but that does not alter the fact that the virtual threat problem meets the definition of a threat.

If a directmate problem makes more than one threat, and all but one of them are virtual threats, does it mitigate the slight blemish?
A threat is a threat, and threats are not defined based upon the ability to carry out the threat.

If one character threatens to knock another into next week, the virtual threat is still a threat (unless these are characters on Star Trek).
 
 
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MatPlus.Net Forum General Questions with terminology