A unique sword fighting style used by Sasuke's son Fugaku before finally passing it to his own child. This particular fighting style involves using many blades as possible, by scattering them around the battle field; this gives the practitioner an advantage and allows them to overwhelm their opponents with a large number of swords. While using the art of infinite sword style, Itachi rather than relying on a single good quality blade, makes use of the thousand blades that are scattered across the battlefield. Itachi does not particularly care about the quality of blades, as long as they serve their purpose. While using this style, Itachi uses a variety of moves and makes use of either a single blade or multiple blades at the same time.
Because there are almost over a fifty blades scattered across the battlefield, Itachi always has a blade, or multiple blades on hand ready for use. Due to the flexibility of the sword style, Itachi can use the blades for various purposes beyond the conventional melee attacking, including use as projectiles, defenses, paths to walk on, increasing speed, pins to hinder the opponent’s movements, course chakra through to make them levitate, and also to attack the enemy multiple times simultaneously.
According to Fugaku, using this type of sword style is not as easy as it sounds, as one much have a natural gift for the arts of swordsmanship, including a better understanding of the various swords styles that exists. Fugaku developed the sword style by carefully observing other swordsman masters and their fighting style, later incorporating some aspects of their sword styles into the infinite sword style. He has also stated that the user of this style must possess quick reflexes and incredible speed, in order to use the style. Many of his peers and clansmen find the infinite sword style rather unorthodox, but due to Itachi's unpredictable and odd nature, this type of fighting style rather suits him perfectly.
Before a battle begins, Itachi uses the Summoning Technique: Thousand Blades, to summon the numerous swords into the battlefield. The swords are scattered across the battlefield in nearly every spot one can see.
Infinite Sword Style: Passing Fang - Itachi begins the attack by grabbing three swords from his surroundings and placing them right in front of the opponent, they are positioned standing parallel to each other and stuck to the ground. By using a fourth sword in his hand, he hits all three of them near their sunken tips, which causes all the swords to slash upwards, in a manner reminiscent of a fang.
Certain Kill: Black Star Big Wave - The move requires Itachi to use a fighting style similar to Strong Fist. Initially it starts with an elbow strike to stun the enemy, then a powerful punch which sends a moderate amount of chakra through the opponent's body which holds enough force to send one flying backwards.
Summoning: Thousand Blades - A summoning technique that allows Itachi to summon a fifty blades into the battle field despite the name of the summoning since he doesn't have the chakra nor control to create a thousand swords. In order to initiate the technique, Itachi must place the summon scroll on the ground. Once the necessary hand seals are done, large amount of smoke covers the area, once the smoke clears away Fifty blades can be seen scattered across the area. This allows Itachi to use his infinite sword style techniques. He can also use this technique to re-seal the blades into the summoning scroll.
Ryuugan (龍眼, Dragons Eye): A dojutsu that mutated from the offspring of a Ryuu Clan Member and one of the son's of Sasuke Uchiha. This deformed doujutsu manifests itself within the left eye of the user. It possesses a number of unique abilities, though it seems to share some similarities with a few other doujutsu. First and foremost, the dojutsu enables the user to visualize the flow and release of chakra. This supernal vision penetrates through objects and physical materials; however the eye is blind to all but chakra. The user sees living beings as networks of vibrant energy, as their chakra networks throb and flow throughout their bodies internally. Furthermore she is able to track the flow of chakra; for example, she is able to see the chakra of a genjutsu flow through the air and affix itself to a target to manipulate them. By tracking these fields and traces of chakra that living persons leave in their wakes, she is able to discern their paths from the environment; he can track them via their chakra signatures, which appear as a trail of hazy mist. Depending on the chakra reserves of the individual, these trails can last anywhere from a few minutes to several weeks. The clarity of the dojutsu's perceptions is another unique trait, unlike other doujutsu such as the Sharingan, which only shows an overall aura of chakra and its colors, the dojutsu possesses an acute level of precision and exactitude in its perception, demonstrating the same level of clarity as the Byakugan. The greater her control over her chakra has become, the more clarity the the user gains. Furthermore the amount of chakra required to maintain this ability is relatively small.