pro-Japanese group; Japanophiles
Refers to a group or faction that is favorably disposed toward Japan, its culture, or its policies. Often used in political or cultural contexts.
He is known as a pro-Japanese lawmaker.
There are many Japanophiles in that country.
Compound of 親 (しん, 'pro-', 'friendly to') + 日 (にち, 'Japan') + 派 (は, 'faction', 'group').