Between Hikaru's novice computer skills and Sai's strength at playing Go, they become the most unbeatable player in the world of Internet Go. From New York to the Netherlands, Sai's has players from all around the globe wondering who is this amazing player!
At the World Amateur Championship, the air is abuzz with interest in Sai whom some of the participants have played online at one time or another. While some think he's a pro, others feel that he might just be the ghost of famed Go master Hon'inbo Shusaku, who Sai taught many years ago. But when Akira's name shows up onscreen, Hikaru gets ready for another rematch.
Eager to take on Sai, Akira doesn't even bother to show up for his first pro exam match. But Sai defeats him, leaving Akira to wonder if it's Hikaru on the other side of the board. When Ms. Ichikawa tells Akira that she spotted Hikaru at an internet café, his instinct turns to intense suspicion.
Summer's winding down and thanks to all his internet playing with Sai, his game has gotten stronger. But there's no time to play at the internet café and with Sai's help, takes on Hikaru's grandfather so he can get the premium Go board and stones he desires.
After a chance meeting in a bookstore, Kishimoto, the captain of the Kaio Go Club, takes Hikaru to a Go Salon to see what kind of player he truly is. Over a game of Go, Kishimoto tells him about Akira's goal of turning pro, sparking Hikaru's interest in chasing and catching up to Akira.
Hikaru returns to the Go club to announce his intentions on becoming an Insei, which angers Yuki Mitani and disappoints the rest of the Haze Middle Go Club. As he breaks the news to the club, Kaga enters the room in an attempt to evade one of the teachers. Upon hearing Hikaru's new goal, Kaga forces him into a Go match that also includes Kimihiro and Yuki!
Even with his new-found love for the game of Go, Hikaru finds it nearly impossible to sit comfortably, let alone beat his opponent during the test. Luckily for him, he discovers that the game is not being decided on wins and losses, but on strength and is accepted as an insei. After the test, he reveals his rivalry with Akira Toya to a pair of skeptical insei, competitively friendly Waya and the contemplative Isumi.
Now that he's an insei, Hikaru's finding that winning is hard to come by. Starting off with six straight losses, Hikaru's at the bottom of the B-league with little hope in sight. Meanwhile, Akira has just become a pro and is gearing up for the Shinshodan Series, where newly-turned pros take on established veterans of the game.
As the Shinshodan Series starts up, the Oza is taken aback by Akira's seemingly easy rise to the pros. Instead of playing a simple exhibition match against the young prodigy, he's going to challenge Akira with everything he's got. Since he's never seen Akira play anyone other than himself, Hikaru can't wait to see this match, if only he can finish up his own match first!
Feeling a bit nostalgic, Hikaru comes back to visit to Haze Middle Go Club, where things have gone from bad to worse. Since Yuki quit, the club cannot participate in school tournaments. Now no wants Hikaru around, fearing that his presence will push Yuki away even further away from rejoining the Go Club.
It's time for the Young Lions Tournament, where 16 newly crowned pros take on the Top 16 Insei in the A-League. While his other fellow Insei keep falling to the pros, Isumi takes on obnoxiously boastful Mashiba, a former Insei who never ceases to brag about his life as a pro. Will Isumi knock off him off his pedestal or continue to fall victim to his endless taunts?
As the Young Lions Tournament winds down, Hikaru loses his match to Murakami 2 -Dan. Anxious to know about how the entire match progressed, Akira presses Ogata Sensei, one of the spectators at the tournament, for answers. But Ogata's got more important things on his mind, such as dethroning Kuwabara-sensei for the Hon'inbo title.
In the lobby of the Go Association building, Kadowaki, a top College player, is looking to brush up on his game before taking the Pro Exam. Enter Hikaru, who with Sai's help, teaches this amateur how the game of Go is truly played. Meanwhile, the battle for the Hon'inbo title continues as Ogata and Kuwabara trade moves, as well as words, in order to psych each other out.
The Prelims for the Pro Exams are about to start! Hikaru starts off on an unlucky streak when he draws Tsubaki, a loud and overbearing biker who uses his time to think about his moves...on the back of his motorcycle. Will Hikaru let this boorish and ill-mannered opponent intimidate him into losing?
In the hopes of helping Hikaru get over his fear of playing adults, Waya and Isumi take him to a Go Salon to take on opponents of a more mature nature. The three of them sit down for a team game and at Waya's urging, makes a bet to clean every stone if they lose. But when Kawai, a bushy-haired cab driver, discovers that Waya, Hikaru and Isumi are all insei, he decides to face Hikaru and see how strong a player he truly is.
At a local festival Akira is asked to play 4 players simultaneously including Kurimoto, a boorish and rude city councilman. To make matter worse, he's been asked by the festival organizers to let Kurimoto win. Meanwhile back at the Go Salon, Kawai and Fukawa, the Go Salon owner, have given Hikaru the task of playing his opponent to a draw!
On the recommedation of a fellow Go player, Hikaru, Waya and Isumi try out a new Go Salon that's different from the rest. There, Hikaru's ignorance about the strength of Korean Go Players is discovered. Insulted by that fact, Su-yong, a Korean insei, challenges Hikaru.
After a contemptuous and intense battle, Hikaru triumphs over Su-yong, leaving his Korean opponent more determined than ever to take on Hikaru once again. At the end of the match, a face from the past lavishes praise on Hikaru, leaving Sai to feel apprehensive and unwanted.
It's time for the Pro Exam and Hikaru's starting off with six straight wins in a row. Can he keep his winning streak going or will his fellow insei knock him off his undefeated pedestal? Akira accepts an offer to tutor Ochi, an arrogant insei who's taking the pro exam with Hikaru.
As the Pro Exam continues, Hikaru learns from his fellow opponents that the road to turning pro isn't as easy as it appears to be. Meanwhile, Ochi starts to get suspicious about Akira Toya's true intentions for tutoring him.
Ready to take on an undefeated Isumi, Hikaru knows he's in for a tough match. But as the match progresses, it starts to look like Isumi's the one who's on the ropes. Can he beat Hikaru or will the pressure finally get to Isumi?
With the pressure mounting, Isumi makes a wrong move forcing him to resign and forfeit the match. As a result of how the match ended, both Isumi and Hikaru's game head downhill as they both run right into a losing streak.
Determined to get his game back on track, Isumi takes on Ochi with a vengeance. But Ochi is more concerned with his final opponent: Hikaru. With only three weeks left until his match with Hikaru, he seeks some assistance from a particular source: Akira Toya.
Now that the Pro Exam is winding down, the stronger players are beginning to distinguish themselves from the weaker ones. The gruff Tsubaki gives his Hikaru a ride on a motorcycle, as well as his dying dream of becoming a pro. Meanwhile, Akira continues to tutor Ochi on how to beat Hikaru.
Now that Ochi has passed the Pro Exam, there are only two spots remaining. With only two games left in the exam, Hikaru faces off against Waya. Can Waya overcome both the pressure of passing and from Morishita Sensei and defeat Hikaru?
As Hikaru takes on Waya to advance towards the pros, Waya notices that his opponent's game bears a interesting resemblance to Sai. Meanwhile, Ochi's confidence cause Akira Toya much worry as Ochi has yet to face Hikaru.
Gearing up for the match, Ochi reveals to Hikaru that he has been studying with Akira Toya in the hopes of learning how to beat him in the pro exam. Does Hikaru have what it takes to beat Ochi or will Akira look to his bespectacled pupil as his new rival?
It's down to the wire as to who will make it into the world of the pros. Will Hikaru upset Ochi, the newly crowned pro, or will Isumi sneak by with his four losses? As word spreads about the pro exam results throughout Haze Middle School, Hikaru eavesdrops on the Go Club and starts to feel left out.
The ever-busy Toya Meijin has finally decided to participate in the Shinshodan Series on one condition: his opponent must be Hikaru Shindo. But Sai sees this match as his only opportunity to take on Toya Meijin. Will Hikaru give up the chance of a lifetime so Sai can play in the match of a lifetime?
From newly-turned pros Ochi and Waya to Go-playing veterans Ogata and Kuwabaru Hon'inbo, everyone's got their eye on this match between Hikaru and Toya Meijin. But little do they know that it's really Sai playing as if he were behind by 15 points.
Feeling the need to cheer up a depressed Sai, Hikaru takes him to an Amateur Go Festival, where they expose a local merchant selling counterfeit Go merchandise and meet Atsushi Kurata, a friendly, but overconfident pro who delights at giving by signing fans for his most devoted fans.
Toya Meijin falls victim to a heart attack and is rushed to the hospital. Hikaru goes to visit him and discovers that he's supplementing his recuperation by playing Go on the internet. As a result, Hikaru begs Toya Meijin to play Sai on the internet which he reluctantly agrees to on one condition...
Now that Toya Meijin is playing Internet Go, the world is abuzz with excitements, watching a professional champion play online. But little do they know, that a challenger of exceptional strength waits in the shadows...
The time has come for Sai to leave has come, leaving Hikaru angry and frustrated. He goes back to his Grandfather's attic and discovers that the Blood-stained Go board, where Sai's spirit once resided, is now clean. In his quest to find Sai, Hikaru takes off for Innoshima, where Sai first appeared to Torajiro, the young man who later became the great Hon'inbo Shusaku.
While in Innoshima, Mr. Kawai stumbles into a Go Salon where, as a result of a misunderstanding, he finds himself owing a lot of money to Shuhei, a formidable Go player who is enormous both in size and talent. But when this top amateur recognizes Hikaru from Go Weekly, he decides to take on this reluctant neophyte pro.
Hikaru goes through old game records to find past matches with the great Hon'inbo Shusaku. While going through them, he becomes engulfed in guilt over not playing enough games with Sai and his subsequent disappearance.