Asukayama park (飛鳥山公園, asukayamakouen) is very authentic hanami spot.
Asukayama Park, also known as Oji Park (王子公園, ojikouen), is located at the Kita-ward of Tokyo. It’s famous for sakura trees. The park was created by Edo-era Shogun Yoshimune in early 18th centery. The purpose of the park was just to be a good hanami spot.
Later, in 1873, the park was designated to be one of the first parks in Japan.
Tourist Info:
Aside sakura, there are many ericaceae and hydrangea in the park, too.
Access
0. From Tokyo station.
1. use Keihin-tohoku line (JR) to Oji Station. (18 minute)
2. walk south (6 minutes)
30 min
Let's learn MJER Iaijutsu. 
映画好き集まれ！ Asukayama Park is the one of the great Hanami Spot in Tokyo. One of the great Shogun Yoshimune build this park about 300 years ago for Hanami. By the time there was not much Hanami spots in Edo (Tokyo). So, he build this park so that all people could enjoy Hanami. This park is the first park placed in Japan.