According to Japanese surname researcher Hiroshi Morioka, the most common full name in Japan is “Minoru Tanaka” (Minoru is the first name, Tanaka is the surname).
Japanese names are written in kanji, or Chinese characters. Morioka believes that many families like to chose first names with kanji that are complementary to the kanji in the surname, and that this is what makes certain combinations particularly popular.
In the name Minoru Tanaka, for instance, the kanji can be interpreted as “to ripen in the rice field.” “This reflects the close traditional relationship the Japanese have with rice and agriculture.”
The second most common full name, Shigeru Suzuki, “incorporates the Chinese characters for “tree” and “to grow thick,” another fitting name combination inspired by agriculture.”
The third and fourth most common full names are Minoru Suzuki and Kiyoshi Sato, but my source didn’t mention what the kanji in these names might mean.