OK so now many of you thinks that mihawk is above shanks which makes him automatically above many younkous but that's not true at all, marine said that they used to fight each other but maybe After losing one arm he asked mihawk to teach him sword fighting because thats the only possible reason since fighting with sword is most suitable style when you have only one arm, mihawk can't take down shanks because of haki and all, they were not fighting they were training........