Three of the chapters in this volume cover a single go game. If that sounds boring, it really isn't, and one of the things I like about Hikaru no Go is that you don't have to be a go expert (as I certainly am not) to follow the dialog about go moves. Obviously it helps to know something about basic moves so you kind of know what you're looking at, but the characters describe everything in terms of "strong" and "weak" moves and invading, a dominating presence, a risky strategy, etc. You could be a total go novice and still follow along.
In volume 6, Hikaru Shindo tests to become an Insei, and despite being relatively weaker than other candidates, he passes because the sensei is impressed at how quickly he has improved with so little formal instruction. (Of course, they don't know about the thousand-year-old ghost who's been tutoring him.) Hikaru walks into his first day of lessons at the Insei school and boasts that Akira Toya is his arch-rival. Since child prodigy Akira has just gone pro, everyone assumes this must mean that Hikaru is a scary-good child prodigy himself. When Hikaru gets trounced in pretty much every game, he receives a much-needed dose of humility.
Meanwhile, Akira is still obsessed over Hikaru despite being convinced (correctly) that the other child is nowhere near his level. Thus his first game against another professional as a pro himself. He gets to play the reigning Oza, or top title-holder. The Oza is a patronizing old curmudgeon who decides to crush Akira when he thinks the boy lacks humility. Instead, Akira plays an all-out game, hoping that Hikaru is watching, and it actually makes for a pretty dramatic three chapters, as the story is about the psychology of the players, not the game itself.
I like the way the series demonstrates that there really is no ceiling in go ability; no matter how good you are in whatever circles you play in, you'll always find a bigger pond in which even the mediocre players can trounce you. And when you become the biggest fish in that pond, there are always bigger ponds yet. Hikaru started out barely able to beat his classmates in a middle school go club. Now he's playing against Inseis, who could probably walk into most go clubs in Japan or anywhere else in the world and beat the pants off everyone in the club, but against professional go players they may as well be beginners themselves. And Akira Toya, who is now a professional, someone who terrifies Inseis, is finding that there are entire ponds-within-ponds here that he has yet to conquer.
The bonus chapter at the end was a cute extra: the cast of Hikaru no Go
putting on a play, "Assassination at Honnoji Temple," about the death of medieval warlord Oda Nobunaga, which, it turns out, had a game of go in it.