Kazuo is a Japanese masculine given name, composed of two kanji characters: 'Kazu' (一) meaning 'one', and 'O' (王) meaning 'king'. This name suggests uniqueness and leadership, implying that the bearer is one of their kind in some aspect. It gained popularity in Japan after the Meiji Restoration due to its association with notable figures such as Kazuo Shiraga, a prominent Japanese painter known for his dynamic and energetic style.
The name Kazuo experienced significant popularity during the early to mid-20th century, with a peak of 48 births in 1919 and consistent high numbers until the late 1930s. After World War II and up until recent years, its usage has been less frequent but still present, with 5 or fewer births per year since 1944.