This series is average [Rating: 6/10]
Yankumi (Nakama Yukie) certainly didn't fit as the heir of a yakuza family. When she went into "Yakuza mode" there were more times I wanted to hide under my blanket in embarrassment than not. She was not credible as a yakuza, everything from her facial expression, stance and the way she spoke was just wrong. If anything, I'd say Nakama Yukie ruined this series for me. I might also add that I don't like Nakama Yukie in general, everything she does feels forced.
Sawada Shin (Matsumoto Jun) wasn't credible as the leader of a gang of delinquents either. I really never understood why he was the leader, he hit a teacher once and acted high and mighty (of course, this is the writers fault, not Matsumoto Jun's), was that it? Can't take much to become a leader of delinquents in Japan. It looked like there were a lot of people who could whoop Sawada Shin's ass just in class 3D, and isn't that usually how a leader of delinquents is born, being the toughest guy around making people respect you with strength? As for the actual acting, I guess he did a good enough job.
Teruo Kumai (Waki Tomohiro) did a really good job in my opinion. He was good both in the serious and less serious scenes. This is probably my favorite character in this series along with Minoru and Tetsu (the two of the four yakuza who live in Yankumi's house who had the most screen time).
Noda Takeshi (Narimiya Hiroki)... I never really understood what this guy did in this series, he was probably just eyecandy for the female audience. There was nothing delinquent about him, he would have fit better in a beauty salon.
Uchiyama Haruhiko (Oguri Shun) and Minami Youich (Ishigaki Yuma) both did good jobs, I have nothing more to add to these characters.
I liked the school staff too, the vice principal could be hilarious at times and the male audience also got some eyecandy here from the English teacher Fujiyama Shizuka (Itoh Misaki)
In Yankumi's house, as I already mentioned, I really liked Minoru and Tetsu, they were hilarious and they actually felt like yakuza. So did Wakamatsu Hiro (Anan Kenji), but unfortunately he didn't really get much screen time. The yakuza boss Kuroda Ryuichir (Utsui Ken) was just as credible as a yakuza boss as my can of coke here next to me. A yakuza boss shouldn't run around screaming "KORRRRRRRRRRA" at everyone, but at the same time he shouldn't feel and look like he couldn't hurt a fly even if he wanted to.
This series is watchable but not recommendable. The comedy does its job, but many of the delinquent/yakuza scenes feel forced, especially when the main character is present. This series is average and gets a 6/10 mainly because of the side characters.