|Volume 1, Chapter 2|
Boundary is the second chapter of the Btooom manga, it focuses on Sakamoto's battle against the strange man.
Ryōta flees from Yoshiaki who bombards Ryōta with Cracker BIMs. As Yoshiaki takes performance enhancing drugs, he recalls his old life on the streets. Near the cliff, Ryōta hides and tries to figure out how to use his BIMs. He throws a couple of BIMs but misses Yoshiaki and explodes seconds later. Ryōta manages to catch Yoshiaki off guard when he is above Yoshiaki. he asks Yoshiaki about Btooom and the IC chip that is embedded in his hand. Yoshiaki laughs at how Ryōta had lost his memories and quickly tosses a Cracker BIM at Ryōta. Exhausted and desperate, Ryōta surrenders only to be blasted by Yoshiaki. While Yoshiaki searches for Ryōta, Ryōta realizes that the IC chip acts like a radar. He figures that hiding is useless with the IC chip.
- The IC chip allows players to track down other players.