Koji (Suna) and her teammates cleared the first phase of the Chunin exams in Konohagakure. The next mission was to reach Sunagakure, but only the first 30 teams who reached Sunagakure would advance to the next stage. Koji and her team qualified for the round, and she even healed Sakura at night when she was stung by a poisonous scorpion.

The next day, Timari instructed all participants that the second phase would be held at Demon Desert, and teams were given either a Heaven Scroll or an Earth Scroll before entering the desert. They then had three days for the entire team to reach the building in the center of the desert, with one of each scroll in their possession.

When searching for a scroll, they saw a Suna-nin being poisoned. Koji and his teammate Ameno healed the Suna-nin, and in return, when the Suna-nin offered their scroll, they rejected it, saying it was her duty to heal them as a medical-nin.

Later on the same day, when Shishio uses his sensing seal technique, Koji and his teammates intercept Sakura, Choji, and Ino. At first, they told them if they gave them the scroll, they would let them pass, but the Konoha shinobi refused, which led to a fight. Koji faced off against Choji Akimichi.

Koji and his team needed help against Choji's strong taijutsu skills. Meanwhile, Shishio's team used chakra to hide from their opponents, but Ino's sensing abilities helped her team find them. Ultimately, Koji's team lost, but there were no hard feelings.

They offered their scroll to the winners but declined since they already had enough scrolls. They all agreed to meet again in the third exam.

However, the Chunin Exams were cut short before the finals due to controversy in the second exam. Gaara decided that reports on each participant would be sent to their respective village leaders to determine if they should be promoted.

Koji got slightly annoyed when Ameno didn't accept the scroll they offered after healing a fellow Suna shinobi. He felt his village would tease him if he took a scroll from someone who was hurt. Also, he acted a bit superior, making fun of a team of Suna shinobi for not knowing their land's dangers.

Koji has messy, dark blond hair and violet eyes. His bangs cover one of his eyes. He wears a light violet top with a brown vest over it, which has a pocket and a scroll attached to it. His forehead protector is on the back of his vest. He also wears black gloves, dark blue shorts, and long, open-toed black boots.

Koji is good at using sand in fights. He can create different things like hammers and shields from the sand if there's enough of it nearby. He's strong enough to use these sand weapons effectively and even block a powerful punch from Choji.