Synopsis:
"Weak Legs" Shirahama Kenichi would rather spend his time reading self improvement books than fighting. However, when he finally gets up the courage to become strong and join his school's karate club he gets forced into a challenge from an upperclassmen who is trying to get him kicked out. He is about to give it all up until he falls for the mysterious new classmate, Furinji Miu. In order to become strong he undergoes rigorous training at the dojo she lives at, Ryouzanpaku. Here he learns from multiple masters their various martial arts such as karate and Muay Thai and corabines them to create his own fighting style. After beating his upperclassmen he soon receives the attention of the powerful gang known as Ragnorak. He becomes backed into a corner and must fight his way out as he becomes stronger and stronger.
Source: MAL
Yes I have seen this. It's a great anime series. You should read the manga, it goes so much further. I dont want to ruin the ending for you, but It is completely epic, Kenichi is one of my favorites by far. He dont mess around.
If you liked Kenichi, you would also like Hajime no Ippo, Boxing anime, similar MC.. but the surrounding characteres verry. I love the Masters in Kenichi, it was really a unique thing.. In Hajime no Ippo there are great characters that back the MC as well.. it has nice development, and a second series. Well worth the watch.