Teaching of English became universal starting in elementary school around 1910. Here is a summary of the history:
This was the situation in 1872 the year after the Daimyos were disbanded:
While on the subject of education, I may mention that there is among
the Japanese of all classes, an universal desire for acquiring foreign
languages, especially English, and other branches of learning. The
principal establishment where foreign instruction is given in Yedo is
the Kaiseijo (school) under the superintendence of the Rev. Mr.
Verbeck, an American missionary. The number of pupils is about 400, of
which 200 are instructed in the English, and the other 200, in about
equal proportions, in the French and German languages. The number of
foreign teachers is fourteen, besides Mr. Verbeck, namely, four
Americans, three English, four Frenchmen, and three Germans.
Vice Consul Dohmen to Mr. Adams, Yedo, February 15, 1872
Commercial Reports from Her Majesty's Consuls in Japan [note Yedo means the
city we now call Tokyo]
Thus in Tokyo we have 400 English students in a nation of 16 million people, but a "general desire" to learn English and other foreign languages.
This was the situation in 1889:
The demand for an English education in Japan is, and has been for
several years, so great that all the native and missionary schools
combined are unable to meet it. The young men and women throughout the
land, in the towns and cities not only, but also in the remotest
mountain districts, are extremely eager to learn enough English to be
able to read, and many are ambitious to speak the language as well as
to read it. The Japanese government has done much to meet this great
and ever-increasing demand.
"English in Japan" by the Reverend T.T. Alexander in Osaka
The Church at Home and Abroad, Sept. 1889
English teaching begins to be widespread in private institutions, but is not government sponsored.
By 1904, due to the Sino war, English teaching became standard in "middle schools", a type of university in Japan. (see Japan by the Japanese: A Survey by Its Highest Authorities edited by Alfred Stead, 1904). There were 26,000 students in about 250 middle schools at that time. This standardization of the subject in colleges resulted in the spread of the curriculum in lower schools, so that English teaching became general by about 1910:
All these boys of Japan are filled with the liveliest interest and
wide-eyed curiosity about America and England. All would like to write
letters to American boyx, for English is taught now in every high
school and every grammar school in Japan.
Letter by Dr. Jordan of the Boy Scouts of America who travelled to Japan in 1911
Boys Life, June 1915