Question: Since my past works didn't require strategic planning skills much, I think than mentioning about my chess skills is a good example for it. What do you think?

Here is my draft:

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> Skills
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> **Strategic planning:** top 50 players in Chess Tournament for Students in City X (2012)
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Answer: 
Strategies in chess boil down to memorising a set of patterns and using them in combinations against the set of patterns your opponent has memorised and combined, then hope they make at least one more mistake than you.

Strategic planning in a business is much more complex:

* you don't have perfect and open and freely accessible information of the game state
* the game is not remotely zero-sum
* the rules are dynamic and with significant regional variation
* you are not in sole charge of your resources or choice of plan
* you are not seeking an endgame, but an open-ended improvement process

Each of these alone makes your chess experience not a brilliant starting point for business strategy planning. At best it will help when you begin learning, but there are other skills which would be far more important in a business setting, like the ability to manage time pressure or to self-develop your skillset for a task.

TLDR: don't bother.
Even though I do, in your case I wouldn't. And certainly not in the Skills section. 

I've always mentioned my chess skills on my resume, but in the Hobbies section. Feedback was never negative, ranging from one quick slightly intrigued question to a longer discussion with genuine respectful interest. In many people's mind chess is linked to intelligence (it's complete crap obviously, there are dumb people in chess as in any other part of the population), strategic thinking etc. It might also be viewed as a sign of nerdiness (again, cliches die hard) but hey I work in IT so I'm already assumed to have a 50% chance to be an autistic geek :) Seriously it's a good way to tell a bit more about myself in a way that is generally perceived positively, and several times served as an ice-breaker once we were done with the regular hr/technical questions. But it's not intended to prove anything regarding my skillset. 

That being said, I would only mention playing chess, not that tournament. To be honest it's just not that impressive. If they show some interest and start discussing your hobby then you can talk about it.