The IC chips are implanted in the player's left hand, and can only be removed when that player is dead. The ultimate goal of the Btooom! game is to collect 8 of these chips and only then will that player be allowed off the island.
An IC chip is an oval glass that is embedded into a Btooom! player's left hand. When it is used, it shines a blue-ish green light. According to Ryōta Sakamoto, the IC chip feels chunky, but doesn't inflict pain.
OperationThe IC chips are mainly used for locating opponents. When a Btooom! player puts some strength in his left middle finger, the IC chip will be activated and an outgoing sonar will spread itself in a circle around the user. When that sonar detects another IC chip (so another Btooom! player), the user will get the feeling of that player's presence and know his location.
But on the other hand, when a player gets detected, he feels this as well. So the located player will know that he has been exposed, so he also knows that someone is trying to locate him.
Also, when a Btooom! player is not moving, he cannot be detected.
In short, a wave will go out of the chip and any opponent in the area will be detected by the chip user, but reveals the user's presence as well.
Counter-useWhen two IC chips are used at the same time, their sonar waves will cancel each other out. They hit each other at the same time and stop working due to interference. This can be used by Btooom! players in battle, so that the one player won't know where the other is located.
Early chip collections
Beware of spoilers ahead!
The picture used in the character gallery (I don't know which is its source, unfortunately; it may be related to the anime, for it describes the situation as very close to the end of its first season) describes the character relationships at some point after chapter 39 but before chapter 51. It features 18 characters in all, with non-sequential numbering (and in one case, a label that is not an actual number). It is a convenient framework to describe the known IC chips and their collecting until that point.
- 01:Ryōta Sakamoto - collected chips from 13, 16, and 17
- 02:Yoshiaki Imagawa - implied (by the graph and his ownership of two bandoliers) to have taken 08's chip. His chip and 08's were taken by another player, as revealed in Chapter 75 of the manga.
- 04:Kiyoshi Taira - took 15's chip, then 14's
- 08:Unnamed, in fact unseen in the manga story proper. Apparently 02's first and sole victim.
- 10:Misako Hōjō - lost chip to 11
- 11:Nobutaka Oda - implied to have taken 02's and 08's chips (but we learn better in Chapter 75 of the manga); known to have taken 10's and 21's; has two other chips from unrevealed players.
- 12:Kōsuke Kira
- 13:Sōichi Natsume - lost chip to 01
- 14:Yoshihisa Kira - lost chip to 04
- 15:Mitsuo Akechi - lost chip to 04
- 16:Isamu Kondō - lost chip to 17
- 17:Masashi Miyamoto - collected chip from 16
- 18:Hidemi Kinoshita - collected 19's chip, later relevant to the plot in chapter 59 page 15
- 19:Hitoshi Kakimoto - lost chip to 18
- 20:Masahito Date
- 21:Tomoaki Iwakura - lost chip to 11
- A:Shiki Murasaki - lost her chip (to 20) before the current game