The passport of his brother, Shunjiro, says Shunjiro was the "eldest son." From that, we can deduce that there was at least one younger son in Shunjiro's birth family. The dates given are based on when Shunjiro was born and when the father, Shuniro Sakaoka, was known to be in the U.S.

In WWI, his draft registration shows he was born 15 Mar 1898 in Japan.  Yonetaru Sakaoka of Desha Lane, Honolulu was listed as someone who would always remember the location of Shigeru.. Shigeru worked as a garage man at Schuman Carriage Company.

A Yonetaro Sakao, born abotu 1874 in Japan, arrived in Honolulu 2 Jan 1909. His previous residence was in British Comlumbia. This Yonetaro Sakaoka, born about 1872 in Hiroshima, Japoan, arrive in Honolulu on 9 Jan 1908. This Yonetaro, a fisherman, lived at 1114 Desha Lane, Honolulu in 1928.  Also listed in 1928 were Shigeru Sakaoa, an expressman at 1189 River; and Mars. Mitsuko Sakaoka, a barber, also at 1189 River.  In the 1911 city directory was Yonetaro Sakaoka (in the barber section).  1912 shows Y Sakaoa as a barber.

This might have been Shigeru Sakaoa, born about 1898 in Hiroshima, Japan, who arrived in Honolulu, Hawaii on 26 Jun 1916. His WWII draft card shows his birth as 15 Mar 1898 in Hiroshima.  During WWII, he lived at 280 N. Beretania Street, Honolulu. He named Horace Hosegawa of  the same address as a person who would always remember his address.

Shigeru  Sakaoka, age 26, married Matsuko Amake in Honolulu on 6 May 1924.  However, though the handwriting is difficult, his parents were listed as Yashitan Murata and Iowa Murata.

In 1930, Shigera Sakaoka, 32,, was listed in Honolulu with his wife, Metsuki, 26; and daughters, Shigeki, 6, and Emeko, 0.

In 1940, Mitsuko was divorced and had reacquired her maiden name of Amaki.  She lived in Honolulu with:

Shigeko Sakaoka, 16
Emiko Sakaoka, 10
George Sakaoka, 7
And her sister and nieces:
Katsuko Amoki, 27
Miyono Amoka, 8
Kiyoko Amoki, 7