It's from a manga ''Nice Summer" by Yachi Emiko
from wiki-addictsManga synopsis - Ouyang Yu Yan meets Xia Ya, for the very first time, she believes they would become best friends. When Xia Ya sees Yu Yan's one-year-younger brother, Lei, for the very first time, she falls in love with him. But how could a plain girl like Xia Ya attract the attention of Ouyang Lei, a cool bishounen model who has a difficult personality?
Zhou Qiao Shan, the kendo captain, begins to like Yu Yan, but Yu Yan believes he likes Xia Ya. Chen Lang Zhu, one of the kendo boys, decided to send a love letter to Xia Ya. Lei laughs at her knowing that it is the first love letter Xia Ya has ever received.
Episode 01 release soft sub by us Intangible FS
can find here
http://www.d-addicts.com/forum/viewtopic_46492_0.htm tread and soft sub