Iwashi is a high level chuunin of the Hidden Leaf Village. He was also an observer during the chuunin exams. While observing he brought one team to the attention of Mitarashi Anko, the team from the Hidden Sand Village, including Gaara, Temari, and Kankuro. They managed to reach the central tower in one and a half hours, but it usually takes four hours to get there.
After The Hidden Sand Village invaded the Hidden Leaf Village; Iwashi, Shizune, Raidou, and Genma were assigned to a mission by the Fifth Hokage. Raidou and Genma followed the Sound Four when they left with Sasuke. The Sound Four activated their Cursed Seals and quickly beat Genma and Raidou. Iwashi and Shizune rushed to help them with their injuries. Iwashi then said he wanted to continue the mission by himself, but Genma warned him that it could be too dangerous and can result in death. The Sound Four were just too strong for them.