Im assuming the rushed ending wasnt deliberate - its like the mangaka finds out it wont be continuing in the magazine and they have 2 chapters left to finish it- i think they'd of liked more.
IIRC Sanada Ikki said he'd wanted this manga to be 3 volumes long, but it was not to be.
EDIT: Forgot to mention that it ended up being 2 volumes long.
EDIT2: Yes, pretty much what happened - author was told he had 2 chapters left.
Also, he did mention the possibility of doing a Saori x Haruna doujinshi work, but it seems he never got around to it...
last edited at Aug 8, 2014 12:33PM