Santoryu is a style of sword fighting where the practitioner wields three Katana; one in each hand and one in the mouth. There are many different techniques for this sword style, including high speed attacks ("Shishi Sonson"), direct hit attacks ("Oni Giri") and compressed air projectile attacks ("Hyaku Hachi Pound Ho"). Roronoa Zoro is the world-famous swordsman of the Straw Hat Pirates who created this style.
Zoro first started developing "Nitoryu" ("Two Sword/Blade Style"), when he first started learning the ways of the sword. Defeated by his rival Kuina 2000 times, this only drove him to become stronger and stronger. One day, he challenged Kuina to the two thousand and first match, confident as usual, only this time, he wanted to fight with actual swords. Zoro fought with his usual Nitoryu, as Kuina fought with her "Ittoryu" ("One Sword/Blade Style"). At the end of the fight, Kuina once again came out on top. That would be the last time that the two rivals ever fought each other, because the next day Kuina lost her footing on some stairs, fell, and died. When Zoro was told this, he was devastated, and he asked his sensei to give her sword, "Wado Ichimonji" to him so that he can carry on their dream to become the greatest swordsman.
It was because of this that Zoro started learning "Santoryu" ("Three Sword/Blade Style), which later drove him to become an extremely powerful swordsman, and Santoryu to be an extremely powerful style. Despite it being an irregular fighting style involving using three swords in an unusual manner involving one in each hand and one in the mouth, this is his most preferred fighting form against several powerful opponents.
Although Zoro has noted that he could settle for any sword no matter the grade as long as he has three, several sub-par swords unable to match Wado Ichimonji have broken in the past, which means that he could never use his Santoryu to the fullest unless he found swords of a greater grade. After finding Sandai Kitetsu and Yubashiri, he could better use this swordsmanship to defeat people such as Kaku from CP9, later replacing Yubashiri with Shusui after its blade was rusted away by Shu.
Zoro can use three swords, two swords, and one sword style techniques. When he uses three swords, the third one (usually the Wado Ichimonji) is placed in his mouth. While using Santoryu, Zoro has a tendency to hold his left hand blade with a "reverse grip", in which the blade protrudes from the bottom of his hand and points away from the opponent. This is likely done to increase the versatility of his attacks, as holding the blade in this fashion allows him to deliver multiple cuts from a variety of angles. A few examples are during his battle with Pica, when he blocked Pica's strike on Ucy, when he uses "Ichidai Sanzen Daisen Sekai", and when he uses "Sanzen Sekai". Several of his attack names are actually puns due to the way some of the Japanese words are combined together. When these words are pronounced together, they can sound like a completely different Japanese word, often referring to cuisine in general, and to sushi in many specific cases. Also, while Zoro is agnostic, some of his attacks have religious references to them. Many of his attacks before and after the timeskip also incorporate animal themes (gorilla, dragon, lion, bull, etc.).
Oni Giri (鬼斬り,Oni Giri?, literally meaning "Ogre Cutter"): Zoro's signature technique. A three-way simultaneous slashing attack. Zoro crosses his two swords across his chest and places the blade in his mouth horizontally behind them. Zoro then approaches the target (usually at high speed) and cuts through by swinging the swords across his chest, resulting in a descending diagonal-crossing slash from both swords while the mouth blade performs a horizontal cut from either the left or right, depending on which side of his mouth he positioned the sword's main blade at. The pun in the name is that onigiri is also the name of a Japanese rice snack (known as fantuan in Chinese), while an oni is a type of ogre/demon in Japanese folklore (also read as a type of "ghost" in Chinese which ties into its on'yomi/pinyin reading). This was first seen used to finish Cabaji and the first technique he used against Dracule Mihawk. It should also be noted that in that fight with Mihawk, the technique's main weakness was discovered. There is a single brief moment when the three swords are all lined up behind each other. If one can block them at that instant, the entire technique will be rendered useless. Mihawk did so by putting his necklace blade against the front most sword when Zoro tried the technique. Doing so however, requires an enormous amount of strength, more so than Zoro himself or else he will just push through the block and connect anyways, as shown with Zoro's battle with Hatchan. This attack has been shown to rival Luffy's Gomu Gomu no Bazooka or Kaku's Bigan in power. This attack is the only one that when it's named, Zoro does not say "Santoryu" before its name.
Yaki Oni Giri (焼鬼斬り,Yaki Oni Giri?, literally meaning "Burning Ogre Cutter"): A variation of the Oni Giri where Zoro's swords are on fire. Should this attack connect, the opponent will also be set on fire. Tying into the above mentioned "onigiri" pun, adding "yaki" to it would change its meaning to "grilled rice ball". Zoro first used this attack to save Usopp from being blown up by Mr. 5. The main flaw of the technique is that Zoro is also being burnt while using this technique. In the VIZ Manga and FUNimation dub, this is called Flaming Oni Giri.
Enbima Yonezu Oni Giri (艶美魔夜不眠鬼斬り,Enbima Yonezu Oni Giri?, literally meaning "Charm Demon Sleepless Night Ogre Cutter"): A stronger variation of "Oni Giri" where the swords are twisted during the slash for added force, resulting in this attack striking multiple opponents instead of one. The pun naming in this Oni Giri variation is due to whenever "Ebi Mayoneezu" is added, the name can also mean "shrimp mayonnaise rice ball" in Japanese; "yonezu" by itself without an extended "e" vowel is also a term for rice vinegar (along with "komezu/komesu"). This was first seen being used against several Marines in the Enies Lobby courthouse. During its use, he generated a steam which made his swords look like they were bending. In the VIZ manga and FUNimation dub, this is called Charming Demon Sleepless Night Oni Giri. As for added visual effects, a cloaked demon (with glowing red eyes in the anime) appears to be standing behind him when he uses this technique.
Tora Gari (虎狩り,Tora Gari?, literally meaning "Tiger Hunting"): Zoro puts his hand swords over his mouth blade and swings forth a forward descending slash with them. At close-range, this can incapacitate at least two average foes at once. When Zoro uses this attack, the aura of a tiger's head is shown behind him. The pun in the name is that "Tora Gari" is also a type of Mohican haircut. Zoro first showed this attack to defeat the Nyaban Brothers. In the VIZ manga, this is called Tiger Hunt, but later in Volume 21 it is called Tiger Trap. In the 4Kids and FUNimation dubs, this is called Tiger Trap.
Santoryu Ogi: Sanzen Sekai (三刀流奥義 三・千・世・界,Santōryū Ōgi: Sanzen Sekai?, literally meaning "Three Sword/Blade Style Secret Skill: Three Thousand Worlds"): Zoro holds two of his swords at an angle against each other and rotates them rapidly while running towards his opponent to create momentum; he then slices up the foe with full speed and power with all three of his swords at once. This attack was first used to try to defeat Dracule Mihawk. According to the name of this attack, this is the ultimate and strongest technique of the Santoryu. It was first used successfully against Oars after 429 chapters since its first appearance, where Zoro dealt three enormous slashes over Oars' body with the technique. Zoro has improved his usage of this over the timeskip, now able to prepare it while hurtling through the air and able to use this attack while his three swords are imbued with Busoshoku Haki. This attack was shown for the first time when he used it against Pica after the timeskip. This technique was the first one of Zoro's old attacks that he uses after the timeskip. It is seen again much earlier in the anime, when a hypnotized Roronoa Zoro used it against Monkey D. Luffy in the Ocean Dream Arc. In both One Piece: Grand Battle Rush and One Piece: Grand Adventure, the move is initiated by Zoro placing his swords in an inverse triangular formation before spinning his two swords together (in the English 4Kids dub, he also mispronounces Santoryu). In the 4Kids dub, this is called Ultimate Three Swords: Three Thousand Worlds, in the FUNimation dub, this was called Three Swords Style Secret Technique: Three Thousand Worlds but was renamed to Three Swords Style Ogi: Three Thousand Worlds then later renamed to Three Swords Style Ultimate Attack: Three Thousand Worlds, and in the Odex dub, it was called Triple Sword Twister: Green Roll. It is a reference to the Buddhist cosmology. When he used this against Mihawk for some reason he spun the two swords in opposite directions, the right hand clockwise and the left hand counter-clockwise.
Toro Nagashi (刀狼流し,Tōrō Nagashi?, literally meaning "Blade Wolf Stream/Flowing"): At a close range, Zoro leans toward the opponent, using two of his swords to block the opponent's attacks while twisting his body around as he is continuously moving to approach and dodge other attacks (if there are any) and eventually cutting through the opponent's stomach with the third sword. It was used in Zoro's battle against Hatchan. Zoro performed an aerial version of this move against Bartholomew Kuma when he used it to effectively evade the latter's rapid Pressure Cannon attack, and would have succeeded to land a point-blank hit had Kuma not blocked his swords with his "paws". In the VIZ manga, 4Kids, and FUNimation dubs, this is called Streaming Wolf Swords. "Tourounagashi" (灯籠流し, lit. "garden/hanging lantern stream/current") is a Japanese ceremony in which participants float paper lanterns (chochin) down a river. This technique is often executed as a counter/reversal in most of the video games it appears in as opposed to a direct attack.
Tatsu Maki (龍巻き,Tatsu Maki?, literally meaning "Dragon Twister"): Zoro spins with his swords to create a dragon-like tornado that both slashes and blows away the target(s). By the time of the Enies Lobby Arc, Zoro achieved enough power to bust apart a tall establishment all the way through the topmost ceiling with this move and was also able to break Tekkai. This is one of Zoro's most powerful attacks. The pun here is "Tatsumaki" means "tornado" in Japanese when written with the Japanese character for "tatsu" (竜) instead of the Chinese character (龍), and is also a type of sushi. In the VIZ manga and 4Kids dub, this is called Dragon Twister, and in the FUNimation dub, this technique keeps its name. However, in some episodes of the FUNimation dub, Zoro calls it Dragon Twister. In the Odex dub, this is called Zoro Tornado. It was first used to defeat Hatchan. The aura of a Chinese dragon is seen accompanying him during the formation of this technique.
Ushi Bari (牛針,Ushi Bari?, literally meaning "Bull Needles"): Zoro executes a multi-hit running attack with two swords held out like a bull's horns. This was first seen being used against Mr. 1. The pun here is that an "ushibari" is a wooden beam used in Japanese homes. This is called Bull Needles in the VIZ manga and FUNimation dub (via the literal translation of the "hari/bari" kanji, since the kanji for horn would actually be 角, read as "kaku" or "tsuno"), and Bull Charge in the 4Kids dub. The aura of a bull is seen accompanying Zoro when he uses this attack. In some video games, Zoro akin to most "rapid striking attacks" may or may not add a finishing blow.
Gazami Dori (蟹獲り,Gazami Dori?, literally meaning "Crab Seize"): All three swords are horizontally parallel, suddenly clamping down on the target like a crab's claw for a guillotine like effect that would normally cut a person's head off. In the VIZ manga and FUNimation dub, this is called Crab Grab. This was first seen being used against Mr. 1. The name is a pun off of "kazamidori", or "weather vane", despite the kanji for 蟹 often being read as either "kan" or "kani". When Zoro uses this technique, the aura of a crab is seen behind him.
Hyakuhachi Pound Ho (百八煩悩鳳,Hyakuhachi Pondo Hō?, kanji meaning "Feng of 108 Kleshas"; furigana meaning "108 Pound Phoenix/Cannon"): Same principle as the thirty six version of the same attack. Holding his two swords horizontally above the shoulder and the other in his mouth in the same direction, and then performs a circular swing that launches three air compressed projectiles spiraling towards the target instead of one or two, tripling the power of the technique, but with Shusui, the air compressed projectiles instead fuse and become a larger and more powerful, compressed air projectile. This attack seems to be as powerful as Luffy's Gomu Gomu no Cannon. This was first seen being used to finish off Ohm. This is called 108 Pound Phoenix in the VIZ manga and FUNimation sub, 108 Caliber Phoenix in the FUNimation dub, and Triple Sword Soaring Phoenix in the 4Kids dub. The attack's name is actually a very heavy pun — it is written out as "Phoenix of the 108 Kleshas" in the manga with a skewed reading attached that makes it "108 Pound Hō" when read out:
Ho means both "cannon" (砲,Hō?) and "phoenix" (鳳,Hō?), however the attached kanji is for "phoenix", making that the literal translation and the "cannon" reading a pun on that, both of which are correct. The kanji "ho" however, is actually for the Chinese creature known as the "feng".
The "pound" part is a skewed reading of the kanji for "klesha" (煩悩,Bonnō?) (the Buddhist term for "worldly desires with evil thoughts"), and it is referring to the caliber of a cannon (a 108 Caliber Cannon would fire a 108 Pound Ball).
Karasuma Gari (鴉魔狩り,Karasuma Gari?, literally meaning "Crow Demon Hunting"): Zoro performs a flying multiple slash technique. This attack is strong enough to cut steel, as it was first seen used to slice cannonballs. This was first seen being used against the Franky Family. The pun is that "kasumagari" is slang for a leg cramp in several regions of Japan, including the one that Eiichiro Oda is from. This is called Raven Hunt in the VIZ manga and the English version of One Piece: Grand Battle! Rush! (dubbed by 4Kids) and Karasuma Raven Hunt in the FUNimation dub.
Gyuki: Yuzume (牛鬼 勇爪,Gyūki: Yūzume?, literally meaning "Bull Ogre: Brave Claw"): The swords are positioned pointing at the enemy. Zoro lunges forward and hits the enemy with great impact. This was first seen being used to shatter T Bone's sword. This attack can also be done in mid-air. In the VIZ manga, this is called Bull Demon Courageous Talons, early in the FUNumation subs and in the Funimation dub, this was called Bull Demon Bold Hooves but in later episodes in the sub, it was changed to Bull Demon Courageous Talons. The ushi-oni, or gyūki, is a horned, bovine head creature which appears in the folklore of Japan. When Zoro uses this attack, the aura of a bull is shown behind him.
Ichi Gorilla (一剛力羅,Ichi Gorira?, literally meaning "One Gorilla"): Zoro flexes his left or right bicep, in preparation for Nigori-zake. "剛力" (gori) means "herculean or great strength" (literally read as "gouriki" and can also be written in kanji as "強力"), while the kanji for 羅 (lit. "silk/thin/gauze") is a kanji used for demon names in Japanese. The pun is of course, "one great strength" and gorilla (though a more literal translation is "strong strength gauze"). This was first seen being used against Kaku. In the VIZ manga and FUNimation dub, this is called One Gorilla.
Ni Gorilla (二剛力羅,Ni Gorira?, literally meaning "Two Gorillas"): Zoro flexes his right or left bicep, in preparation for Nigori-zake, as a follow-up for the above technique. As above, the pun is "two-strong strength" and gorilla. This was first seen being used against Kaku. In the VIZ manga and FUNimation dub, this is called Two Gorilla. The version of this technique used in the Pirate Warriors games even causes a ring of slashing energy to emerge around Zoro that launches opponents.
Nigori-Zake (二剛力斬,Nigori-Zake?, literally meaning "Two-Strong Strength Slash"): After using both Ichi and Ni Gorilla, Zoro swings his swords so that the tips meet when they hit the opponent, with the swords in his mouth and left hand being held at the same level and the right's hilt dropping at an angle, akin to the Hirameki. The pun here is that nigori zake also means 'unrefined sake (Japanese Rice Wine)'. This was first seen being used against Kaku. This attack is powerful enough to disperse Kaku's Bigan. When he uses these attacks, his biceps seem to get almost 2 or 3 times bigger, being similar to Urouge's ability of increasing his muscle mass. His arms also bulk up like Chopper's while using Arm Point. In the VIZ manga, this is called Two Gorilla Cut while in the FUNimation dub, this is named Two Gorilla Slash. When performing this technique Zoro is accompanied by the aura of a gorilla; the first instance he has used it was in midair, while it is only in the Pirate Warriors games he has used it on the ground.
Hyokindama (豹琴玉,Hyōkindama?, literally meaning "Leopard Harp Orb"): Zoro jumps forward while spinning in the air, forming a ball shape with his blades. This is basically a feinting maneuver, so even if the target manages to read the pattern of this attack and move out of Zoro's trajectory, they will still be cut as Zoro careens past them. This was first seen being used against Kaku. In the VIZ manga, this is called Leopard Spinning Balls, and in the FUNimation dub of One Piece: Unlimited Adventure, this is called Hyokindama and in the FUNimation dub this is called Leopard Spinning Shot. The kin or koto (琴 or 箏) is a traditional Japanese harp, while the term can be read as Kotodama ("The Power of Words"), but the pun is that it can be misread as "Hyou Kintama", "A Leopard's Testicles." When using this technique, the aura of a leopard accompanies Zoro. In some video games (such as in the Pirate Warriors games), this attack is also visually shown as Zoro spinning forward akin to a drill.
Daibutsu Giri (大仏斬り,Daibutsu Giri?, literally meaning "Great Buddha Cutter"): A series of horizontal sword slashes that are powerful enough to cut apart a small building. This is the first new Santoryu technique Zoro has used since losing Yubashiri. This move can also be performed vertically. This was first seen being used to provide Sanji with "ammunition" for his "Jenga Ho" technique. This can be misread as dai ("big") and butsu-giri ("roughly chopped"). In the VIZ manga and FUNimation dub this is called Great Buddha Chop. In Gigant Battle 2, Zoro combines this attack with Karasuma Gari, where he performs the aforementioned technique before he reaches the ground with the actual Daibutsu Giri.
Yasha Garasu (夜叉鴉,Yasha Garasu?, literally meaning "Yaksha Crow"): Zoro spins like a rolling wheel towards his enemy while continuously thrusting his swords at the opponent. The attack leaves cuts shaped like crows' feet. In the VIZ manga and FUNimation dub this is called Demonic Raven This was first seen being used to carve up Oars' arm. Yaksha is the devil which embraced Buddhism, with its Japanese name literally meaning "Night Splitter" (the latter kanji is a term for a fork in the road). It is also a pun on a three-legged crow called Yata Garasu, a reference to the three rows of crow feet-shaped cuts Zoro leaves. While using this technique, the aura of a Yaksha is seen behind him. In the anime, the aura of a crow is seen.
This is a list showing the attacks Zoro used for his Santoryu after his two years of training with Dracule Mihawk. The techniques he uses are enhanced versions of his old attacks. Though these were the only named techniques used in the manga after the time-skip, in the anime Zoro is shown to still use his weaker pre-timeskip techniques also. As revealed in the Dressrosa Arc, Zoro can also imbue his swords with Busoshoku Haki, making the attacks even stronger.
Santoryu Ogi: Rokudo no Tsuji (三刀流奥義 六道の辻,Santōryū Ōgi: Rokudō no Tsuji?, literally meaning "Three Sword/Blade Style Secret Skill: Crossroad of Six Paths"): An alternative secret technique he developed after two years of training with Mihawk. Zoro manages to bend his body and swing the swords in the form of an inverted "S" shape while performing a vertical spin, slashing the opponent six times simultaneously so fast that he did not seem to move at all. This technique's named after the Six Paths of Buddhism, that is said to the be the six states where a person is controlled by their desires and conquering them is able to transcend their animal nature; tsuji also means crossroad, which ironically ties into the infamous term tsujigiri (crossroad cutting/killing). It was first used against the Kraken, to cut one of its tentacles and divide it into six pieces. In the video game One Piece: Gigant Battle! 2 New World, this technique involves six repeated slashes, ending with a vertical spin. In the FUNimation subs and dub, it is called Three-Sword Style technique: Crossing the Six Paths, while in the VIZ manga it's Three Sword Style Crossing the Six Paths.
Kokujo: O Tatsumaki (黒縄・大龍巻,Kokujō: Ō Tatsu Maki?, literally meaning "Kalasutra: Great Dragon Twister"): A much stronger and more effective version of "Tatsu Maki", where Zoro performs the same action. He spins to create a dragon-like tornado that both slashes and blows away the targets, but the attack keeps going like an actual whirlwind and cuts up anyone who gets caught in it. While the old version only gave the victims small cuts and was able to break a Tekkai (like Kaku's) at its full potential, this new version seems to be able to cut through thick steel with ease. It was first used against the New Fish-Man Pirates. According to Zoro, the whirlwind will not cease until its targets are sent to hell, a befitting description of the technique's name, as "Kokujo" is Japanese for Kalasutra, one of the eight levels of hot Naraka (hell) in Buddhism. In the anime, after his introduction, the dragon figure looks like Momonosuke's dragon form.  In the VIZ manga, it is called Three Sword Style Black Rope Dragon Twister. In the FUNimation subs, it is called Black Rope Dragon Twister, and in the FUNimation dub of Film Gold, it is called Black Rope Great Tatsu Maki (as in all of these cases, "kokujo" literally translates to "black cord/straw rope").
Rengoku Oni Giri (煉獄鬼斬り,Rengoku Oni Giri?, literally meaning "Purgatory Ogre Cutter"): A much stronger version of "Oni Giri", where Zoro still faces away from the opponent and waits for them to come. He then turns around and leaps towards the attacking opponent. This may be a way to make his already lightning-fast triple-slash even more sudden. The effect of this attack leaves an X-shaped stream of blood and generates a powerful shockwave that destroys the surroundings. While the old version could break Hachi's six swords, this new version can easily break the eight swords of Hyouzou (a swordsman Hachi was not able to defeat since childhood) who was extremely doped with Energy Steroids. It was first used to defeat Hyouzou. In the VIZ manga and FUNimation subs and dub, this is called Purgatory Onigiri. This is one of Zoro's Oni Giri variations where there are no alternate food-based puns in its naming.
Ul-Tora Gari (極虎狩り,Uru Tora Gari?, literally meaning "Extreme/Polar Tiger Hunting"): A much stronger version of "Tora Gari", where Zoro does the same movements, he puts his hand swords over his mouth blade and swing them forth a forward descending slash with them. The aura generated by Zoro seems to be the same as the original Tora Gari, the aura of a tiger's head. While the original version was able to withstand against powerful human enemies like the Nyaban Brothers or Mr. 1, this enhanced version is able to match the strength of a dragon. The pun is that the name is a portmanteau of 'ultra' (pronounced urutora in Japanese) and 'tora' (tiger in Japanese). It was first seen used against the Punk Hazarddragon. In the VIZ manga and the FUNimation subs, this is called Ultra Tiger Hunt, and in the FUNimation dub of Film Gold, it is called Ultra Tiger Trap.
Senhachiju Pound Ho (千八十煩悩鳳,Senhachijū Pondo Hō?, literally meaning "1080 Pound Cannon"): A much stronger and powerful version of "108 Pound Ho", where Zoro does the same exact movements as before, holding one of his swords horizontally above the shoulder of his sword arm, and then performs a circular swing that launches the air compressed projectile spiraling towards the target. This new stronger version possesses the ability to cut through a large stone wall (in this case, Pica). The name implies it is ten times as strong as the previous version. This was first used against Pica. In the VIZ Media this is called 1080 Pound Phoenix and in the FUNimation subs, this is called Ten Thousand and Eighty Caliber Phoenix. The aforementioned puns within this series of techniques still apply. In some video games, such as Pirate Warriors 2 and 3, as well as Burning Blood and Jump Force, the technique is distinguished from other variations via being a blast of multiple sword-cutting-beams-crossed-together instead of the iconic wind tunnel blast.
Santoryu Ogi: Ichidai Sanzen Daisen Sekai (三刀流奥義 一大・三千・大千・世界,Santōryū Ōgi: Ichidai Sanzen Daisen Sekai?, literally meaning "Three Sword/Blade Style Secret Skill: Great Three Thousand Great Thousand Worlds"): An enhanced version of "Sanzen Sekai". Zoro delivers massive slashes to his opponent one after another. This technique can be done airbone and is capable of cutting through a large amount of solid stone with ease. This was first used against Pica, slashing several times at his giant stone body to lure him out and defeat him with the final slash of the move. When Zoro used this technique he used Haki on his swords to make them more durable and the attack even stronger.Three Thousand Great Thousand Worlds, often shortened to simply Three Thousand Worlds or Great Thousand Worlds, refers to Buddhist cosmology. In the Viz manga and FUNimation subs and dub, this is called Billion-fold World Trichiliocosm.