Maiko Nakamura - Let Go

Edit (1/15/18): It's been almost 5 years since I first heard this song and decided to share it after realizing how difficult it was to find it! I'm glad many of you have enjoyed it! Maiko Nakamura is still producing albums (latest one is 'Love Covers'), so please support her.

There are 3 official versions of this song that I know of:
M-Flo - Let Go ft. Yoshika
Maiko Nakamura - Let Go
Flower - Let Go Again
(Shimizu Shota & Solidemo have made unofficial covers as well.)