Whose autograph is this on a Sailor Moon pencilboard?
nhahtdh's comment is correct.


  I guess it's Usagi, where the A part is actually 月.


A photo of a merchandise from Sailor Moon S shows that the first character looks like 月【つき】 (moon).



Image taken from のり's yaplog, a Japanese blog

However, the signature seems to be a corrupted version of 月【つき】のうさぎ (Moon rabbit), as clearly shown in another photo of SuperS' merchandise.



Image taken from ゆかりん's Twitter