Most upvoted comment
Who would win if every country sent their leader to fight to death?(r/AskReddit)
Not only is he a black belt, he is a very good black belt. In judo, a black belt signifies that you have learned all the techniques. Putin is much higher than that, showing that he has a very strong proficiency with them as well.
He has his own signature move.
Edit: for those wondering, his signature move is the Haraigoshi.