Iwao is a unisex Japanese given name that has been used for both males and females since ancient times. It is typically written as "岩雄" in kanji, which can be translated to "rock" (iwa) and "hero" (yū). The name Iwao was particularly popular during the Heian period (794-1185), with notable historical figures bearing this name, such as Iwao no Hime, a legendary princess from the Nihon Shoki. Today, Iwao remains a rare but timeless choice for parents in Japan seeking a traditional and unique name for their child.
The name Iwao saw a significant increase in popularity between 1914 and 1921, with the highest number of births in 1921 at 20. However, there was a sharp decline afterward, with fewer than 15 births per year from 1923 onwards. The total number of births over this period is 178.