Ittoryu

Ittoryu (一刀流 Ittōryū?, literally meaning "One Sword Style") is literally using a single sword fighting style. It is the fighting style used by most Swordspeople in the Hedgehog Piece universe, however, most have seen to adapt or even formulate their own unique variation of the style. Such as Drake with Tekiō and Zone with his Reverse Ittoryu. These variations all have their own unique sets of abilities that come with them, by which the user creates, making Ittoryu one of the more versatile and diverse swords style.

Regular Ittoryu
As it is titled, this is the original variation of the Ittoryu style, usually being the most common and knowledgable form of the style. Throughout Hedgehog Piece, many have shown their use of this style, even if it is not their signature form or use of it. Most proficient swordspeople tend to have use this style at one point and then adapt it to their own form of it.

Used by:

Zinzuki Kerulaii
Not his signature style of swordsmanship, but used it when Hamiki had limited Zinzuki to use one sword instead of four.

Crime Boss Hamiki
His signature style, being a rather fearsome and effective swordsman while using it.

Tekiō
Used by:

Drake Mealei

Geogre

Reverse Ittoryu
Used by:

Zone Tuseil

Templar Ittoryu
Used by:

Charles Tala

History
Ittoryu is the most common of fighting styles used by swordsmen, most likely because all other sword forms are came from this one. It is unknown who first uses this style.

Ittoryu Attacks
Exile Breaker: Zinzuki's only known Single-Sword technique so far. He dashes at the opponent, sliding the tip of his blade towards the ground before cutting up and around in a full arc. It was seen cutting through Volt's attack. Seen here

Turbulent Maelstrom: Hamiki's most powerful attack, and what he claims gave him his 22mil bounty. He spins around at a great velocity, then dashes at his opponent, putting all the force he's gathering into a single strike. Seen Here