|Please be aware that this article contains spoilers to Season 3 of the anime.|
His surname is Shimabukuro. In Japan, surnames are listed before given names.
|Japanese Name||島袋 岩男|
|Height||159 cm (5'2")|
|Reach||155.4 cm (61")|
|Date(s) Retired||March 1995|
|Previous Affiliation(s)||Mensore Okinawa Seaside Gym|
|Previous Trainer(s)||Mensore Coach|
|Wins by KO||12|
|Manga Debut||Round 418|
|Anime Debut||Round 1 (Rising)|
|Voice Actor||Egawa Hisao|
Known as the "Ryūkyū Warrior", Shimabukuro hails from a small fishing village in Okinawa and trains at the Okinawa Seaside Gym. He longed to fight with Ippo in a great battle between men of the sea. He was the first challenger to successfully and seriously exploit one of the Dempsey Roll's weaknesses.
Iwao retired after losing to Ippo to focus on his fishing duties and protecting the reefs.
Before Ippo's fight with Sawamura, it was revealed that Shimbaukuro's only loss was to the latter. He could have lost to Sawamura much earlier than round 4, but Sawamura decided to play with him instead.
|LOSS||Makunouchi Ippo||KO||7(10) & 2:15||1995-03-21||Tokyo, Japan||
"Submarine Wars" Japanese Featherweight Title Match
|LOSS||Sawamura Ryuuhei||Decision||4(4)||199?-??-??||??||Japan Rookie King Tournament|
|WIN||Okita Keigo||KO||1(?) & 0:32||199?-??-??||??||A Class Tournament|
Though even shorter than Ippo, his body is like a steel fortress, bulky and cabled with muscle.
Shimabukuro is a in-fighter who is even shorter than Ippo. This mean he has to step for the close range for his fights. His body is cabled with muscles that give him great power. He has great punching power, where even Ippo admits that Shimabukuro's power is greater than his, but the Ryukyu warrior isn't as fast as the latter. Shimabukuro is shown to be extremely durable, showcased when he took on Ippo's Dempsey Roll head on by hitting simultaneous punches against it. The seaman's greatest attribute is his stamina. He is able to hold his breath under water for 14 minutes, and his stamina outlasted Ippo.
Shimabukuro's is a in-fighting expert. Thanks to his layers of muscle he never doubts his raw strength, but only wants to engage the opponent by either turtling and blocking everything or a non-stop infight. He's a careful fighter who will keep slowing down the opponent with as many body blows as possible. He aims to not only kill their legs but have them completely exhausted and unable to move, and will take almost any blow moving towards that goal, as he views boxing as a contest in stamina. He was capable of weight shifting during his fight against Ippo in their zero distance battle with each other. Coach Kamogawa stated that the Ryukyu warrior was a boxing genius equal to that of Miyata.
Like Ippo, Shimabukuro's short height means he cannot use hit and away tactics at all; he always has to press forward to enter an in-fight. Out boxers are his natural enemy.
He lost to Ippo after trying to trade punches with Ippo during the Dempsey Roll; Ippo's endurance proved greater than Shimabukuro's.