Nine Puzzle

Nine Puzzle is a 2001 Mayu Sakai-written Shojo.

Nine Puzzle is a simple story about a boy and a girl and billiards. Mika Sawamura is a very shy second year student at school. She's alone and confused with no concrete dreams of her future. One day she decides to check out some pool at the billiards room. After watching him play pool, she develops a crush on Kaede Minakami, a classmate of her's. The story goes on to show how one game can bring a couple together.

Tropes used by the manga:

 * Bishonen: Especially Minakami.
 * Crash Into Hello: Mika falls over backwards in her desk onto Minakami.
 * Hands-On Approach
 * Loners Are Freaks: This is first thought of Minakami.
 * Shrinking Violet: Mika
 * The Stoic: Minakami
 * When He Smiles: Mika first begins to like Minakami because of the smile he wears while playing pool.