Talk no Jutsu (also known as Therapy no Jutsu), commonly abbreviated as TnJ, is Naruto Uzumaki's strongest jutsu. With it, he can talk to the most evil, depressed, and twisted people and make them change their entire life's ideology in a matter of minutes.
This jutsu was taught to Naruto by his mentor Iruka Umino when he tried to save Naruto even though the latter was blamed for the death of the former's parents. TnJ also seems to be Iruka Umino's only jutsu. In chapter 655, it is revealed that Naruto's mother, Kushina Uzumaki, also had a talent for TnJ, but it does not disclose to what extent Kushina can control this jutsu. It is hinted that Hinata Hyuga also has a penchant for TnJ when she forced Naruto to question himself after Neji's death. TnJ can be activated by uttering a specific word, which, when used uttered repeatedly, results in the controlled person and Naruto entering Talk no Jutsu dimension and the target falling deeper into the jutsu. For example, Naruto's activating word is Dattebayo, Kushina's word is Dattebane, Iruka's activating word is obviously Naruto. Boruto's Dattebasa hints that he similarly possesses the genetically inherited predisposition for TnJ.
Apparently, the TnJ (and the resistance to it) can be passed on to the next generations. This can be seen with Asura descendants Hasirama and Naruto possessing natural TnJ talent while Indra descendants Madara and Sasuke are mostly impervious to TnJ. There is also reason to TnJ can be inherited vertically, with Boruto inheriting his father's ability.
Asura Otsutsuki Edit
Asura, one of the sons of Hagoromo Otsutsuki, is noted to be the inventor of TnJ. With his friendly personality and his mantra of relying on others for his strength, Asura was primed at a young age to develop TnJ. This was first seen when he convinced villagers living near the God tree to rely on themselves for their prosperity. This technique was so momentous that it set up the Naruto universe; Asura's success with TnJ convinced Hagoromo to choose him as his successor, leading to Indra's jealousy and betrayal and culminating with their continuous reincarnations as Hashirama and Madara and eventually Naruto and Sasuke. Ironically, Asura's failure in TnJ-ing Indra was also the first recorded failure of the technique.
Naruto Uzumaki Edit
Naruto's TnJ is widely thought to be the most successful in the entire Naruto universe, with a near 100% success rate that is only broken by Madara Uchiha. This innate strength is likely due to Naruto being a descendant of Asura--the creator of the original TnJ thousands of years ago.
Against Zabuza Edit
The first recorded use of TnJ (appearance-wise) was observed during the Land of Waves Escort Mission Arc when Naruto talked to Zabuza Momochi. He said a few sentences about how Zabuza shouldn't treat Haku like a tool, culminating in Zabuza crying and getting himself killed.
Against Neji Edit
After that, Naruto used TnJ in the Chunin Exams against Neji. Naruto continuously used small bits of TnJ on Neji throughout the fight and then blasted a finishing TnJ-enhanced uppercut punch right up at him. When Neji was lying on the ground defeated, Naruto slipped in a little bit more TnJ to finish him off. By the time Neji was taken to get healed, the TnJ had already taken effect.
Against Gaara Edit
During the Konoha CRUSH arc, Naruto next used TnJ against Gaara. At first it didn't work, so he had to fuck it into him with a TnJ enhanced headbutt. The TnJ seems to be transferable as Gaara gained the TnJ ability after his encounter with Naruto though his technique still leaves a lot to be desired.
Against Tsunade Edit
In the Search for Tsunade arc, Tsunade was subjected by Naruto, whose attitude reminded her of Nawaki and Dan, into multiple flashbacks until she could hardly grasp for breath. While it was not clear whether Naruto used TnJ on her, due to an absence of an extended philosophical and ideological dialogue, it is speculated that Tsunade fell for the TnJ variant: Remind-me-of-my-loved-ones-jutsu so hard that she became Naruto's fangirl, placing her utmost important treasure and faith in him and even almost got herself killed by Orochimaru to protect him.
Against Nagato Edit
One of the most momentous displays of TnJ was seen during Pain's invasion when Naruto confronted Nagato in person. When normal TnJ didn't was not able to budge Nagato, Naruto created a new variant of it called Sage Art: Talk no Jutsu and Sage Art: Flashback no Jutsu. This new TnJ variant, fueled by the natural energy of the earth, was so strong that it made the pure evil, baby-killing, nuke-making Nagato turn into a sissy Naruto fanboy and kill himself to revive all the casualties from his invasion on Konohagakure. It should be noted that from this point on, simple TnJ is no longer enough, forcing Naruto to develop more advanced and powerful variants of TnJ to subdue his enemies.
Against Killer B Edit
Prior to the start of the Fourth Shinobi World War, Naruto used TnJ on Killer Bee to make the latter train him. When proven to be ineffective, Naruto invented another strong variation of TnJ called TnJ: Brofist no Jutsu. This variation is a special one since it did not contain the toxic dialogue of merchandising. He bolstered this with a little Rap no Jutsu to convince the rapper jinchūriki and it worked like magic.
Against Kurama/Kyuubi Edit
The universal effectiveness of TnJ was in full display when Naruto was able to make the Kyuubi submit to his ninja way. Naruto told the bloodthirsty Kyuubi that he'll "do something about his [Kyuubi's] hatred". As the Kyuubi--having been inside Naruto since his birth--is very familiar with TnJ, the usual variant of the technique was rendered moot. This marks the first time when TnJ alone was insufficient to subdue the target. With knowledge on the origin of the tailed beasts, Naruto sought to finally control Kyuubi by evolving the jutsu to one that's actually useful: Action-speaks-louder-than-talk-no-jutsu (ASLTTnJ), on display when he freed the other tailed beasts from the reanimated jinchūriki. Since then, the Kyuubi (now known as Kurama) has unquestionably joined forces with Naruto. ASLTTnJ was so effective that Kurama and Naruto ended up referring to each other on a first-name basis.
Against Obito Edit
Obito Uchiha is the only known Uchiha to be TnJ-able by Naruto. Unsurprisingly, mere TnJ was inadequate and Obito ends up strangling Naruto. In response, Naruto developed Punch no Jutsu, bringing Obito to a new level of TnJ. Using a combination of TnJ and Flashback no Jutsu augmented with a synergy of Sage Mode and Tailed Beast Mode, Obito was punched so hard that he was put into flashback and started to TnJ himself back from his sociopathic and puppy-love inspired emo worldview.
Against Sasuke Edit
Sasuke Uchiha has been blessed by Kishimoto to withstand this horrid technique for 15 long years. This divine level of resistance is thought to be the result of Sasuke being a descendant of Indra--the first person to withstand the TnJ by the first ever TnJ user Asura. Withstanding multiple barrages of TnJ from Team 7 and several more from Naruto for 15 manga years, Sasuke appears to have learned and developed a dark version of TnJ of his own. This TnJ, similar to Naruto, is likely among the strongest to ever exist due to Sasuke being a descent of Indra--the first person to ever resist a TnJ (from Asura).
Sasuke's unique TnJ was seen when he seemingly appeared to be TnJ-ed by Hashirama. To everyone's surprise, Sasuke used an advanced form of TnJ that made Hashirama and even Tobirama TnJ themselves into supporting his ideals.
Sasuke's TnJ resistance came to a close during the last part of the Kaguya Otsutsuki Strikes arc during the closing final battle between him and Naruto. In their final confrontation battle, Naruto and Sasuke, with their own advanced forms of TnJ, fought while communicating telepathically. The battle ended in a tie, with both ninjas lying on the the ground with their arms cut off. Being his keikaku (means plan) all along, Naruto activated the ultimate and most lethal variant of TnJ: TnJ-Blood Ties. By mixing his blood together with Sasuke, TnJ Blood ties finally allowed Naruto to completely brainwash Sasuke to the extent that not even Kishimoto could save him. The technique was so severe and effective that Sasuke ended up marrying Sakura--a woman he never showed romantic interest in, and admitting that Naruto is his equal and best friend.
Several years after succumbing to Naruto's TnJ during the Konoha crush arc, Gaara was finally able to master and display his TnJ prowess during the Five Kage Summit when he asked the other Kages, "When did you forsake your yourself?" This skill was repeated during the Fourth Shinobi World War when he inspired the Allied Shinobi Forces as well as psychologically wounding Kabuto's reanimated corpses. His TnJ finally met its match when he miserably failed against Sasuke, who was just too emo.
Hashirama Senju Edit
Initially, it would appear Naruto's Talk no Jutsu pales in comparison to Hashirama's. The latter's Talk no Jutsu seems to be the most effective, converting Sasuke and Orochimaru to the good side, something that even Naruto could not do. However, flashbacks then revealed that Hashirama Senju's TnJ was insufficient when he failed to bring back Madara Uchiha to the good side prior to their natural deaths. This failure may be the single most important event in the entire Naruto universe as it basically sets up the entire plot, at least before Masahi Kishimoto started that Zetsu and Kaguya bullshit. Moreover, while being a natural at using TnJ, Hashirama has very low resistance against TnJ. This was seen when Sasuke used TnJ on him, convincing the First Hokage to blindly support Sasuke despite the latter's true and more anarchist intentions.
Itachi Uchiha Edit
Itachi Uchiha has a variant of the technique called Izanami which traps the opponent in an endless time-loop until the victim is TnJs himself. This was used to convert Kabuto away from the dark side.
Boruto Uzumaki Edit
Boruto may have used TnJ on Sumire Kakei, when the latter wanted to destroy Konoha by summoning the beast Nue. He was not only able to change Sumire's mind, but was also able to turn Nue from a rampaging beast to a loyal puppy. There were signs before this incident, as Boruto's "dattebasa" was a hint to his hidden potential for using the TnJ.
Despite the seemingly all consuming power of TnJ, there are a few ninjas who have initially shown resistance to it. These include Uchiha Obito, Orochimaru, Uchiha Sasuke, Uchiha Madara, Haruno Sakura, the fourth Raikage, Indra, and Boruto Uzumaki. However, towards the end of the Naruto: Shippuden manga, only Uchiha Madara and Indra was shown to be completely impervious to the technique.
Madara Uchiha Edit
Madara Uchiha is the only shinobi known to be able to resist such a powerful technique probably due to the fact that he created a counter jutsu to it during his time inside the cave. The resulting technique, Give No Fuck no Jutsu, can cancel any form of Talk no Jutsu. This technique was developed in response to his being a victim of Hashirama's Self Sacrifice Talk No Jutsu a few years before he was able to dispel it, likely due to him being a reincarnation of Indra--the first ever person to resist TnJ.
Indra Otsutsuki Edit
Indra's resistance to TnJ was fueled when when he didn't get daddy's attention and wasn't chosen as successor of Ninshu. He declared war on his father and was only stopped when Asura, failing to subdue him with his TnJ, used his full power to defeat him. Refusing to capitulate, he declared that he will eventually destroy his father's work, even at a next life. As a result, his descendants, Madara Uchiha and Sasuke Uchica, was also blessed with innate TnJ resistance.