Next day Saito and Co found a ship after negotiating with the owner he finally agreed to take them to the Land of whirlpools. On their way Saito couldn't use the added weight technique otherwise he will sink the ship with the added weight.
Saito decided to train his lightning jutsu, for a long time he had an idea about a jutsu that uses lightning to attack from far away distances. In this world most jutsus are either large scale jutsus or mid-range or close-range ones. Saito remembered reading an article about a certain weapon that used electricity to increase the velocity of projectiles to a ridiculous level. Saito knows that electromagnetism and electricity are highly tied and a great number of the machinery in the old factory he worked at used it. Standing far away from the rest of the ship's crew and his companions he tried creating an electromagnetic field using his lightning release. Two days passed and he finally managed to create the field around his hand. Moving to the second phase of his training he tried to create a barrel made of chakra to his surprise not all of the physical laws can be applied, chakra by its nature defied the laws he knew from his old world. He found easy to create a barrel. For outsiders his hand was surrounded by a condensed mass of lightning chakra. Maintaining the barrel drained his chakra really fast. After stabilizing it Saito finally held a shuriken in his palm, due to the electromagnetic field the shuriken started floating. Slowly moving his chakra he controlled the shuriken and stabilized it. Using his other hand to stabilize his aim Saito took a deep breath. Aiming at the sea's surface far from the ship he finally launched his attack. The shuriken was revolving at a crazy fast speed the moment it was released it traced a red line in the air and as soon as it collided with the sea surface a huge explosion was released. Everyone on the ship was shocked and in panic but after Saito explained that he was testing a new jutsu he created he was harshly berated by the captain and Karin. Saito based his jutsu on a weapon from his old world so he took the same name for his jutsu: "Lightning release: Railgun".
After analyzing the jutsu he knew that it can be used to attack from great distance but it was close to impossible for him to use it mid battle, it took a great deal of preparation before he could attack. So he could only use it to snipe enemies from long distances, but he believes that with greater control e should be able to use it as easily as his other jutsus. For the rest of the travel, Saito continued his gate opening training, last time he managed to control his chakra with the third gate opened, so now he started training his fourth gate, his chakra was raging at first but slowly it started to return inside his body, his increased control and stronger body helped him contain the raging chakra and slowly he no longer leaked chakra. After all the chakra was controlled Saito started his fifth gate training but unlike the fourth gate he couldn't advance as fast and he could only slowly try to control it, with his current level of chakra control it will take a long time before he could control it but for the moment he can use his chakra mode with the fifth gate open.
One day later they finally reached the land of whirlpools, after paying the captain for his services, Saito and co started moving deep inside the island the Land of whirlpools was destroyed because of their prowess in sealing arts. Slowly they moved towards the Uzumaki compound one they entered, they started looking around, after some time they found a hidden chamber, if it wasn't for the bad state and rundown structure of the building it would have been close to impossible for them to find that hidden passage. After moving slowly down the stairs they finally reached what looked like an old archive filled with scrolls and on a wall a bunch of weird masks where hanged on the walls.
Saito: "Don't touch anything."
Saito slowly approached the scrolls, after closely examining the he saw a small seal on each and every scroll, it looked simple at first but after further inspection he saw that the seal was much more complicated than it appeared and if he used a normal unsealing technique all the scrolls present will be destroyed.
Saito: "Karin can you put some of your blood on this scroll."
Karin approached, after biting her finger she smeared a little bit of blood on the seal. Directly after coming in contact with the seal her blood was absorbed and the seal started changing and soon the scroll opened.
Looking at the content he found them to be sealing techniques.
Saito looked at Karin.
Saito: "Are you interested in learning sealing techniques?"
Saito: "This is the Uzumaki clan's legacy. You are the second person I met with the Uzumaki bloodline, the other one is Naruto the nine tails Jinchuriki. It is your right to learn everything but I would like to ask you to let me have access to the Historical records and any other subject other than sealing arts. "
Soon after Karin started unsealing the scrolls, Saito started was reading the historic records while Suigetsu and Jugo moved out roaming around the compound.
A week passed and Saito finally found some interesting information, it talked about the sage of six paths, his legacy the origin of chakra and what followed.
Saito was shocked because the only mention he found about the sage of six paths was in legends and myths he found in some library books. But to his surprise the records her where quite precise and even the origin of the Biju was there. Saito finally learned found the goal of the Akatsuki, they want to revive the ten tails, he has no idea what they wanted to use it for but he knew that it shouldn't be something good.
After even more digging he found another information the chakra created by the god tree wasn't the same as the natural chakra, this world already had natural chakra before the god tree, even the god tree absorbs the natural chakra in order to create the chakra fruit. People gained their own chakra source after the appearance of Kaguya.
One of the ancestors of the Uzumaki clan was a hermit who lived in seclusion, he didn't have chakra and even after Kaguya appeared he didn't gain it. But in his meditation he managed to harvest the Natural chakra at its purest level, he didn't transform into a stone statue, but his body became the perfect vessel of natural chakra reaching a great level of power but he never used it and spent his life as a simple villager his descendants finally married a descendant of Asura Otsutsuki. Saito was really interested because he knew that usually one needs to contact an animal sage. The current known sages are the toad sage and the snake sage. But the Uzumaki descendant managed to learn it without outside help, even Hashirama Senju managed to learn Senjetsu with the help of his Wood release, the wood release is one of the strongest types of powers and can suppress the Biju, Saito believes that the biggest reason is its close nature to the God tree whish by its nature absorbed Natural chakra. But he also believes that his relationship with the Uzumaki clan gave him access to the records allowing him to perfect his senjetsu.
Saito knew that it would be hard for him to get his hand on a Toad or Snake contact and he also knew that even if he learned it won't be as pure as the senjutsu learned by Hashirama and The Uzumaki ancestor.
Saito kept reading trough the records about history and some simple techniques used by the clan. He also found the way used by the Uzumaki ancestor to train his senjutsu.
Meanwhile Karin was learning the sealing techniques at an astonishing speed, she managed to learn the majority of seals and also learned some forbidden sealing techniques, and each one of the masks had a special use some for sealing some for unsealing.
Another week passed by and Saito tried feeling natural energy but without the outside assistance it was really difficult to feel the natural chakra.