First off who could forget the emotional graduation of the Elders Club from Hello! Project. Although Mitsui worked with few members of them she was still in the graduation.
Then Mitsui started of this year by being the only member to host Yorosen! for 2 weeks in a row on her favorite things: Pets! Included a large photo of her own dog Leo
Then another big thing is Mitsui was placed in her second subgroup: Gurdians 4 which out lasted the expected 2 single run the previous group had.
And who forget Musume's huge announcement that they were going to be heading to America for Anime Expo?!
And once she returned from the USA Mitsui took part in a stop animation film called Yume no Hakoniwa. It also featured Hello! Project members (past and present) Abe Natsumi, Iida Kaori, Tsuji Nozomi, Yasuda Kei, Yoshizawa Hitomi, Ogawa Makoto, Tokunaga Chinami, Kumai Yurina, Sugaya Risako, and of course Mitsui.
Next was Risa and Mitsui riding the giant spider in Yokohama which was originally used as display only. So they are some of the few people who ever got to ride it.
Then shortly after that was a reunion with former Musume members to perform Love Machine for former member Yaguchi Mari who was in a tricycle race as part of the hexagon channel.
Later this fall we had the FC bus tour with Koharu, JunJun, Reina and Mitsui. I believe there was 11-12 buses that brought around fans to hang with our girls. And a mini concert which had an Osaka Koi no Uta duet from Reika.
And of course there was the singles that made this year great! Starting off with Naichau Kamo which started the rend of solo shots for each girl. Than the #1 single Shouganai Yume Oibito than there was Nanchatte Renai, 40th single and it reached 70k. Finishing up this year was Kimagure Princess which was Mitsui's 10th single in Musume. A good year for Musume so far.
Than the most important thing in my mind this year had to have been the Nine Smiles tour. The tour that ended the longest stead line up in Morning Musume history. The graduation of Kusumi Koharu from Morning Musume. This is my mind has been the most emotional event of the whole year.
And those were some of the most important events in the year of 2009 for Mitsui. Honorable mentions would have to Mitsui's placement in Tanpopo# as well as Musume's return (Mitsui's first) appearance on Music Station. It was a fun 2009 for me and Musume. So let's see were 2010 will take us!