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A very strong player can manage and can just know how to manage a thousand positions. I get it; it's a very arbitrary number. So then you have the world champion who could do more. But, again, any increase in numbers creates, sort of, a new level of playing. And then you go to the very top, and the difference is so minimal, but it does exist. So even a few players who never became world champion, like Vassily Ivanchuk, for instance, I think they belong to the same category.

Source: www.businessinsider.com
A very strong player can manage and can just know how to manage a thousand positions. I get it; it's a very arbitrary number. So then you have the world champion who could do more. But, again, any increase in numbers