Tokyo is literally a big international modern city. I went there at the end of September to take part in a Hackathon hosted by BizReach(a Japanese company). In the meantime, I spent some of time for city sightseeing.
I lived Shibuya(渋谷), where many IT companies based. It is also convenient to take subway at Tokyo as other big cities like NYC, Beijing, HK. I also visited Akihabar(秋葉原), Asakusa(浅草), Ueno(上野) in Tokyo. There are two famous towers in Tokyo, one is Tokyo Tower(东京タワー), another is Skytree. And Roppongi Hills is also a high-rise where you could enjoy the view of the whole Tokyo, especially for Tokyo Tower. There are also many well-known spots, like Sensoji Temple(浅草寺), Ueno Park(上野公園), Tokyo National Museum(東京国立博物館), Kabukichō(歌舞伎町), which are worth going to.
Japanese food is super awesome. You could see Ramen and Sushi everywhere in Tokyo, and also, Tempura, Unagi, Yakitori are all very famous. I also tasted the beef there, it is soft and delicious.