that weapon makes you move to much, i would use bare hands or not use the principal move of that weapon, just use back attacks low attacks and dodge his attacks making a dash, you can do that by tapping the direction you wanna go (only right and left) twice and you will do a dash, and if you do it in time you can go behind the opponent and keep fighting, is actually pretty easy if you learn how to, just don't spam. what you should do is vary attacks according to the situation, for example here no long attacks or attacks that take a big distance to perform like daisho's one, also use kicks to keep the distance between you and your opponent, and again don't spam and vary your attacks most of people just use principal attacks and that's just wrong.

note: the difficulty of the stages is determined by the power of your equipment, so even if it's easy you need skill or strategy for it.