Sometimes sponsorships do work like this. But sometimes they do not. Some players get a sponsorship and then sort of are playing with that product because they are sponsored by the company rather than because they want to. But sometimes sponsorship works differently. When a player is so good, so well know, such a marketable commodity, sometimes they just play with exactly what they want and go to the companies and say, "sponsor me" and get the sponsorship. I think part of the DHS thing for the Chinese players might have to do with obligation and nationalism, but I do not think they would be using them if they did not like them. As players they are too good to use something they really don't like. I have no doubt that Jike is just using exactly what he likes.
I cannot see him using something because of some company or contract, or following those kinds of rules.
I know there are stories about things like Wang Hao using a particular Stiga blade with a DHS handle. I have also heard stuff like that they can get something like Tenergy with a DHS lable on it. And perhaps the older guys, sponsorship went to companies they did not 100% want. But I do think Jike and Long are using what they want. I think Wang Liqin is now as well.
There have been players caught by their sponsors using Tenergy. So I doubt that anyone is using Tenergy because they have too and don't like it.
And those DHS rubbers are amazing for looping with the forehand.