Zone (ゾーン Zon) is a term referring to a player's state when they reach their maximum potential. It is a superlative of regular concentration and focus. The conditions to enter this state vary from each person.
One fundamental requirement to enter the zone is also to have an extreme amount of love and passion towards the game. Furthermore, the player must be highly talented, ejecting potential candidates such as Himuro.
This term is frequently used in not only real-life basketball games, but also in other sports as well when a player is on a very good streak of form during a particular game. So far, only Aomine, Murasakibara, Akashi and Kagami have achieved this state. During the Winter Cup finals; Mibuchi, Hayama, Nebuya and Mayuzumi were all one step close to entering the zone as well due to Akashi's influence, but did not enter it.
According to Midorima, even top players that are focused without the Zone can only utilize up to 80% of their potential during a game. When a player enters the Zone, their eyes will be shown emitting currents of electricity, indicating the player's deep concentration. The colors of the electricity is the same color as their eyes (i.e. Aomine has blue eyes while the electricity is also blue). The vision of the player becomes fully monochrome and their hearing is completely filtered.
The basic requirements for entering the Zone needs the player to have unwavering passion towards basketball. This requirement goes along with also having to meet the user's independent conditions, in most terms, desperation of winning or the thrive for competition. During Seirin's quarter-finals against Yōsen, Aomine further reveals that a second requirement is needed to enter the zone that is talent. Aomine explains that while Himuro is very good player, he is only as the best an ordinary man can be and thus is incapable of ever entering the Zone.
It is also mentioned that entering the Zone a second time will be much harder, as the user becomes naturally dependent on using the Zone having to know the existence of it. This is proved by Kagami when he was desperately forcing himself to enter the Zone for a second time, but to no avail. Daiki Aomine further states that to enter the Zone, one must not think of entering the Zone, as wavering thoughts will only disrupt the flow of concentration. Kagami was later able to enter the Zone after completely letting go of the desire for it.
Nearing the Winter Cup finals, Aomine revealed some more information about the conditions of entering the Zone to Kagami. He says that everyone has a different "trigger" for entering the privileged state of the Zone. He makes it clear that just knowing your personal trigger won't make entering the Zone easy, but it doesn't hurt. For Kagami personally, this trigger is apparently the will to fight for his friends, his team.
The downside of the Zone is that the stamina of the user is quickly drained. The player cannot stay indefinitely in that state the whole match.
Being in the Zone is like sinking into water. The more the user uses the Zone, the more they sink. Once they hit the bottom, the user uses 100% of their potential. However, there is another door, even beyond the Zone. Aomine describes this as another stage of the Zone, which is much stronger. This door, is however, guarded by a mysterious gatekeeper who is standing in front of it. If a user wants to open the second door to the Zone, they would have to pass the gatekeeper and open the gate. The mysterious person who is guarding the second door is presumably another self of the user that has hit the bottom of the Zone. Meaning, the users would have to surpass themselves in order to open the second, larger door. 
It was revealed later on that the person in front of the gate is not a gatekeeper, but actually Kuroko. It is presumed that due to the nature of Kuroko's ability, misdirection, he is the one who opens the second gate to the Zone. When the gate is opened, the Zone relies on coordination play of the player's teammates, meaning they would have to sync their play styles with the Zone user. It is noted that Aomine could not open the second door due to his lack of team play and promotion of individual play as an ace. The person standing in front of Aomine's gate, is as well Kuroko. When a player opens the second door, it is known as Direct Drive Zone.
Aomine (Anime) | Aomine (Manga)
When Aomine finds a worthy opponent, he will reach his full potential. Under this influence, he is "in the Zone", which means that nobody else can stop him unless he or she is in the Zone as well.
Only the very best of the elite players are granted permission to enter the Zone, yet Aomine casually forced his way in. Opening the gate to the Zone means opening the gate to your full potential, the full 100% of one's capabilities and abilities. In Aomine's case, his speed doubles at the least, his power increases drastically. His ability to score from anywhere escalates and Aomine's skills becomes even more overwhelming.
Because of Aomine's past victories, he hadn't been this much pressured than in the match against Seirin High, more specifically, Kagami. He started to enjoy playing against his first real opponent in some time and this feeling of enjoyment and excitement opened the gates of the Zone for him.
The difference between his Zone to Kagami's or Murasakibara's is that the two accidentally entered Zone while it seems that he entered through his own will.
Kagami (Anime) | Kagami (Manga)
When Kagami is in the Zone, his reflexes, speed and especially jumping power are greatly augmented. Kagami accessed the Zone for the first time when he was under the pressure of losing to Tōō again and wanted to protect everyone against the ace of Generation of Miracles, Aomine.
In the match against Yōsen during the quarter final round of the Winter Cup, Kagami activates the Zone for the second time. This time, he is even capable of shooting a 3-pointer without fearing to miss. Against all odds, Kagami who does not specialize on shooting from a far distance enters the basket. Whilst in the Zone in this match, Kagami is also capable of overpowering Murasakibara who specializes in strength and render Himuro's Mirage Shot useless.
Before the finals of the Winter Cup, Aomine also revealed to Kagami that his condition to activate the Zone is when the latter is in a state of desperation to fight for his teammates, this being Seirin. Kagami upon acknowledging Aomine's advice, is then capable of activating the Zone right at the start of the match.It is also noted that Kagami can only execute Meteor Jam while in the Zone. This is because Meteor Jam requires an extreme amount of jumping power to throw the ball into the basket.
Murasakibara (Anime) | Murasakibara (Manga)
According to Aomine and Kise, in terms of ability, he meets the requirement to enter the Zone but unfortunately, he would never be able to because he was assumed to not have the most basic term needed: the love for basketball. However, such assumptions were proven wrong when Murasakibara surprisingly did enter the Zone. At the brink of despair and exhaustion against Seirin High in the quarter-finals of the Winter Cup, including Kagami already in the Zone, Murasakibara opened the gates of the Zone. His power grew substantially and his strength along with speed became greater than before. This is proven when Kagami in the Zone still needed Kiyoshi's assistance in order to block Murasakibara from executing Thor's Hammer. However, not much of this was shown, since Murasakibara's body was near exhaustion and Kagami's Meteor Jam already ended the game.After the match, Murasakibara claimed to quit basketball, but broke down in tears not soon after. This makes it clear that Murasakibara does have a burning passion for basketball, in contrary to what was previously believed, which enabled him to enter the Zone.
Akashi had knowledge of the Zone before witnessing the match of Seirin vs Tōō during the Winter Cup, but after seeing Aomine enter it, Akashi was surprised at his potential and he searched for his own trigger to entering the Zone and finally found it. After he defeated Mibuchi, Hayama and Nebuya on a three-on-one battle, Akashi states that his trigger is when he stops relying on his teammates to win and instead decides to grasp victory by himself. His Zone would only be used as a trump card during situations where Rakuzan would surely lose.
When Akashi entered the Zone during the fourth quarter of the finals game against Seirin, his speed and reaction time increased drastically. It is assumed that he combined it with the Emperor Eye to stop Kagami who was also in the Zone. While in the Zone, Akashi's speed and agility is not matched by ordinary players even Kagami while he is in the Zone. However, Seirin managed to stop Akashi with the combination play of Kuroko and Kagami, where Kuroko uses his Quasi-Emperor Eye to predict Kagami's movements and move in the opposite direction to intercept Akashi. This Emperor Eye tactic was used to stop Akashi twice which resulted in Akashi losing his stamina and getting out of his Zone. After using the Zone, Akashi's performance decreased drastically due to physical fatigue and mental shock.
Rakuzan High's "Zone"Edit
When Akashi's real self surfaced, he started using his Emperor Eye to perfect the passes to his teammates. That way, those in his team no longer needed to worry about receiving the passes, since Akashi calculated the trajectory, speed and strength of said passes to the point those who received them could think of their next move and start moving before even touching the ball, and thus, Akashi's teammates could improve their performance, though not to the usual 100% granted by the Zone, but to 90% of their ability, as stated by Riko. The Rakuzan players did not enter the Zone, but are one step before entering it.
- ↑ Kuroko no Basuke chapter 165, page 16
- ↑ Kuroko no Basuke chapter 164, page 3
- ↑ Kuroko no Basuke chapter 232, page 17
- ↑ Kuroko no Basuke chapter 261, page 16
- ↑ Kuroko no Basuke chapter 270, page 16
- ↑ Kuroko no Basuke chapter 270, page 17
- ↑ Kuroko no Basuke chapter 134, page 4
- ↑ Kuroko no Basuke chapter 134, page 13
- ↑ Kuroko no Basuke chapter 133, page 8
- ↑ Kuroko no Basuke chapter 232, page 16
- ↑ Kuroko no Basuke chapter 232, page 17
- ↑ Kuroko no Basuke chapter 168, page 6
- ↑ Kuroko no Basuke chapter 168, page 9
- ↑ Kuroko no Basuke chapter 169, page 11
- ↑ Kuroko no Basuke chapter 260, page 15
- ↑ Kuroko no Basuke chapter 260, page 17
- ↑ Kuroko no Basuke, chapter 268