At least it outsold Rain... But it's safe to say the field strength factor was higher in IML/YH, comparing between Rain's #2 with two significant competitors but managed to get one over (SDN48 but not Tackey & Tsubasa) and IML/YH's #3 with two competitors that ends up being top two monthly for the month of January...
Let's keep up the good, constant work! I'd bet YUI gets significantly better in her next single