Summary
Boruto surpasses Minato by improving the Flying Thunder God and creating a new jutsu. Boruto's Flying Raijin has its own limitations and advantages, including using toads to mark his location. Boruto's Uzuhiko Rasengan is a deadly technique, and mastering Perfect Sage Mode could be next.
Boruto: Two blue tornadoes demonstrated that the protagonist was on his way to surpassing his father Naruto, but it seems that he has also surpassed his grandfather, Minato, by improving his strongest jutsu and signature move: Flying Thunder God (Flying Raijin).
What makes the comparison between the two is that Boruto has reached an even higher level in the skills that Minato was extremely proficient at. By far the most surprising technique Boruto has learned while he was away is the Flying Thunder God, a technique created by Tobirama Senju but perfected by Minato. It is unclear who taught it to him, but the official Boruto database has revealed that Boruto's flying thunder god is completely different from Minato's.
Boruto has developed a new technique based on Raijin's flying
Boruto improved his grandfather's signature technique
Not much information about this jutsu has been released, as it could play a big role in the future and will be fully explored. According to the limited information on the website, Kashin Koji helped Boruto create his own version of Flying Raijin and it could be considered a different jutsu even though Boruto explicitly used the name. It has more limitations than Minato's, but no examples are given.
Based on what has been shown, it can be hypothesized how Boruto's version differs from Minato's. One major difference is that Boruto used it to travel between dimensions when he followed Code to the Ten-Tails' hideout. Minato has never used it like this and it is unknown if he could do it since he never had the opportunity to do so. Interestingly, Boruto had to concentrate for a few seconds before teleporting to the dimension. However, he can use Flying Raijin as quickly as Minato in the human world, as shown when he fought Mitsuki and used his sword to teleport.
The biggest difference between the two is that Boruto has yet to mark a living being, which means he can't. Instead, he planted a toad carrying a marked object on a person and can then teleport. He did this during the fight against Code and later when he rescued Sarada from Hidari. This is probably the biggest disadvantage to Boruto's Flying Raijin, besides the huge amount of chakra needed to activate it, but fortunately, Boruto excellently turns this weakness into a strength.
Additionally, he not only uses the toads to mark a person, but also communicates with them. As shown in chapter #11, Boruto uses different markings on objects, which allows him to “save” different locations to teleport to, giving him great flexibility. The toads can then tell him which spots he should teleport to as well. The toads also give Boruto advice during battle, as demonstrated when one of them urges him to run away when they realize how powerful Boruto’s new villains: the Two Blue Vortex are.
Boruto surpassed Minato in a different way
Boruto Just Takes Rasengan to the Next Level
Along with the Flying Raijin, Minato relied heavily on the destructive Rasengan he created for Kushina. This technique has been passed down through many generations. From Kakashi, Naruto, and Konohamaru to Boruto, this jutsu has undergone various improvements, but Boruto's version of the Rasengan is by far the deadliest jutsu. Known as Uzuhiko's RasenganThis is an instant death sentence for anyone hit by it.
Uzuhiko works by using the rotation of the Earth and hitting the opponent with it. This chakra enters the person and continuously rotates, completely disorienting the victim and disrupting their perception and senses. Furthermore, it gradually damages the person until they die. The only way to stop this technique is to stop the rotation of the Earth, which is impossible, or if Boruto himself disables it. It can be said that Rasengan Uzuhiko is one of the strongest techniques in the Naruto series. Minato tried to create a new variation of the Rasengan but was unable to do it, but Boruto did and created an incredible jutsu.
Minato possesses three chakra natures but barely uses them. This may be because the Flying Raijin and Rasengan are very reliable, but Boruto always uses all three chakra elements he has to unleash their full potential. The only thing left for Boruto now is to master Sage Mode perfectly and surpass Minato in all his techniques. Considering how Boruto: Two blue tornadoes It was revealed that Kashin Koji, an expert in Sage Mode, was Boruto's teacher, which is most likely true.
Source: Naruto official website.