"Otaku culture" in Japan came from people with particular tastes in specific culture that developed into their own subculture – in other words, a specific type of cultural obsession. In Japan, the label "Otaku" (used also as a noun) relates mostly to young men who are into video games, cartoons/manga, anime, and science-fiction – even collecting figures, dolls, games, and magazines (apparently not only in Japan, hint: The Big Bang Theory) :)
Anime costumes and digital bands
Otaku culture evolved into a modern cultural "thing" that has spread around the world. Even in Prague, you can find a Japanese grocery selling cosplay apparel. Explanation: cosplay (costumes + play) is another original element of Otaku, with many people dressing up as cartoon or anime characters. These days there are numerous cosplay events in Japan and worldwide, the phenomenon has even brought to existence so-called maid cafes such as Cafe Athome where Otaku people can relax, talk and be silly with cosplay maids.
People idolizing particular characters have formed special idol groups, and they organize daily live shows, such as AKB48 for instance – an idol group with a special theater in Akihabara. Otaku style audiences of mostly men hold lumica glow sticks and swing them around in unison, yelling their favorites idol's name and singing along together. Momoiro Clover Z is another very popular group but their fan base is more gender neutral. Some men even prefer complete digital idols who are actual anime characters to the living ones. They go to concerts, watching a big screen and chanting to this digital anomaly, having fun... In the end, it is quite harmless and cutely obsessing.
Young Japanese in closets
Idol culture existed in Japan before, but thanks to new markets booming because of Otaku culture, these adolescent idol groups have made a comeback again. Otaku culture has also migrated to China, Thailand and Indonesia, which have their own idol groups, resembling the original Japanese ones. Otaku men are commonly known to be introverts, but there is also a famous non-fictional exception that has become a great hit in Japan, inspired books, drama shows and movies. The story is about a timid Otaku man helping several women from a drunk groping man on a train. This Otaku man eventually married one of these women, and that is how the famous story of Densha Otoko (Train Man) came to being. The story became recognized by many common folk in Japan with Otaku culture at its peak.
Halloween beats Valentine's Day
Japanese otaku and cosplay culture and the pagan Halloween holiday has fused together into an enormous event in Japan. There are parades for children and adults together with parties held throughout the during Halloween week. In 2014, the Japanese Halloween surpassed Valentine’s Day in terms of consumer spending, and it is now in 2nd place next to Christmas. The estimate of consumer spending for Halloween in Japan now is approx. 110 billion yen, or around 810 million euros. That's what you call a business!
Otaku culture is a subculture that has evolved from closeted young men to a more open style, where people are able to share their interests, hobbies and even obsessions with one another. This is not just restricted to video games, cartoons/manga, anime, and SF. You can be an Otaku with anything, such as cars, music, or even language. It’s great when you can lose track of time for something you love to do.