I might give 7 to its anime, but i shouldn't give that to the manga. it such a great storyline and good climax ending. even it is considered as sad-ending manga, but this is the best choice for its ending. i can't imagine about Kobayashi-sensei when he makes this manga as happy-ending for the romance. It will be sucks as Usagi Drop's ending.
This manga is funny, but in other time, the environment turns into a serious one. it explicitly explains about WW2 in Japan in a serious way for the climax.
As person who lives in a country that ever colonialized by Japan, actually i hate this kind of plot.. hey but it is objectivelly great!
the art is good, even i remembered that i hate this anime art in the first time.
i don't know why the manga is underrated, but actually this is a very must-to-read manga. funny, entertaining, emotional, and good ending formula for sad-ending story. it may be great if you buy this manga physically
thank you Kobayashi-sensei for making this such of great manga!