The close relationship between Japan and Indonesia has created a very good impression of the Japanese among Indonesians, especially in Jakarta. This has led to more Indonesians getting interested in Japan, and even the rise of communities and fandom.
A few of these communities include music lovers (these fans break break into sub-groups of Japanese pop, Japanese rock, Japanese jazz, and Anime or game music), anime and game lovers (or better known as otaku), Japanese Culture enthusiasts, model kit hobbyists. These interesting categories cast a wide net of interests into different segments in Indonesia, mainly the children, teenagers and adults separately. The local influencers have taken the lead to strengthen the communities in Indonesia, routinely organising numerous Japanese Matsuri (or festivals).
While there are alot of Japanese-related communities in Jarkata, one that stands out is the Nippon Club from Bina Nusantara University (I was former member). Most members are university students from Bina Nusantara University, and their diverse interests in Japan include music, anime, game, and culture. They meet weekly, and organise two Matsuri held in a year. One is a big event, a show that is usually held at a big venue, with partnerships with big sponsors, and the other smaller event is held in campus area.
Jakarta Japan Club is another noteworthy community that organises an annual cultural matsuri in Blok M area, offering many activities, such as Bon Odori. Blok M is a well known area that the Japanese in Jakarta like to visit, because they have authentic Japanese department stores, travel agencies specially catering to the Japanese, Japanese bars and pubs, also Japanese restaurants. That is why the area is usually booked for the matsuri.
You can find other Japanese fan clubs here in Jakarta with their own unique interest and matsuri. Be sure to visit one when you visit Jakarta!