Chakra Flow

refers to both the flowing of chakra through an object as well as any technique that increases the potency of a weapon by flowing chakra through it. Usually, elemental chakra is used to flow through bladed weapons in order to either dramatically increase their various pre-existing properties or to gain additional advantageous effects. The user must be touching the tool to initiate chakra flow, but direct contact with the weapon is not necessary to maintain chakra flow. Similarly, techniques such as Kakuzu's Earth Release: Earth Spear, Rōshi's lava armour and A's Lightning Release Armour are used to increase close-quarter combat offence and defence by flowing chakra directly through the user's body. However, whether through an individual's body or weapon, the exact effects observed are entirely dependent upon the respective nature and amount of the chakra used.

The known variations of chakra utilised include:
 * Wind chakra, as explained by Asuma Sarutobi, is used in order to increase the sharpness of bladed weapons, so much so that in the hands of an experienced user even small blades are capable of piercing substantial rocks easily, leading to his assertion that this chakra is unparalleled offensively in close and mid-ranged fights. This effect is achieved by utilising two opposing chakra currents, which are ground against each other in such a manner that they sharpen one another into fine pieces.
 * Lightning chakra, as applied to weapons, provides a similar sharpening effect to that of wind, with the addition of inducing numbness. However, this is instead achieved by inducing high-frequency vibrations within the object, granting it even more cutting power than standard wind techniques. Also, when A flowed his lightning chakra directly into his own body, it was capable of electrically stimulating his nervous system. This resulted in an increase in his reaction time, raw speed, and defensive power to their utmost limits.
 * Earth chakra seemingly increases the defensive power of an object to its utmost limits, by further reinforcing the inherent properties of the material involved. However, the application of this variation has only been observed through Kakuzu flowing it directly into his own body, where it resulted both in his skin becoming as hard as diamond and an increase in the overall destructive power of his physical attacks.
 * Fire chakra engulfs the desired weapon in intense localized flames, which follow the subsequent path of the object in question, incinerating anything which comes into direct contact.
 * Yin–Yang chakra does not conform to a single defined list of beneficial effects unlike other chakra natures, instead imitating the properties of the techniques used by the individual in question, as demonstrated by Shikamaru Nara's usage of chakra flow.

Asuma Sarutobi carried special Chakra Blades that were fabricated from a material that absorbed chakra easier, in order to more effectively create these unique effects, which later fell into the possession of his student, Shikamaru. He also taught Naruto Uzumaki the basics of this technique.

Trivia

 * Although the use of chakra flow techniques have been seen throughout the series, the actual term, 'Chakra Flow', was first used by Karin in the Invasion of Pain Arc, when she observed the use of chakra flow by Killer B.
 * During his final battle with Itachi Uchiha, Sasuke infused a Fūma Shuriken with lightning chakra to increase its sharpness.
 * Although Darui and Omoi have yet to show any named techniques that involves chakra flow, Darui has infused his Cleaver Sword with lightning chakra to immobilise Suigetsu Hōzuki, as well as thrown a lightning-infused shuriken to break a katana that Kisame Hoshigaki was holding. Omoi has channelled lightning chakra through his sword to diffuse Deidara's Explosive Clay.
 * In his battle against Sasuke, Danzō exhales wind-natured chakra onto a kunai which expands into a sharp blade shaped like a scimitar. In the anime, he does the same to shuriken, increasing their range and cutting power.
 * The dual swords Kiba, wielded by Ameyuri Ringo and Raiga Kurosuki, are imbued with lightning to make them the sharpest swords ever forged; whether this is by default or provided by the user's chakra is unknown.
 * In the anime, a ninja cat was able to use chakra flow through his claws to deflect weapons.