Koi x Kage is two volumes of so-sweet-it-will-rot-your-teeth shoujo romantic goodness.
Story (7): Orphaned middle school girl moves in with distant relative; she and their boy (of the same age) quickly fall in love. Volume 2 jumps to their high school years, when they actually get to attend the same school, where it turns out the boy is very popular. Being a shoujo manga, you'd never have seen that coming... unless you've read any other shoujo manga, I suppose. Okay, so there is nothing new or original to the story, but it's told well (if a bit too quickly).
Art (6): Pretty
standard shoujo fare, but the character models are consistent, and it gets the job done.
Character (8): The first volume basically only has two (human) characters, and they are both just fun to watch. Hinako is sensitive and tries to hard to impress--not unsurprising for someone constantly trying to fit into other people's homes and families. Subaru is a bit too honest, somewhat oblivious, and extremely caring--pretty much exactly what Hinako needs, given her background. And they both love animals, which just dials the cuteness factor up to 11.
Vol. 2 introduces Subaru's best friend (a girl), who hits it off immediately with Hinako and (shockingly!!!) kind of likes Subaru. She's nice enough, but perhaps not explained as well as she should be... but then again, she does her job in the plot and is by no means annoying, so maybe that's all that matters.
Enjoyment (7): It will make you smile. You might never laugh, and you'll certainly never be uncomfortable or have to think any deep thoughts or anything like that... but who doesn't like to smile?
Overall (7): If you like your romances short, shoujo, and coated in sugary goodness, Koi x Kagi makes a perfectly good after-dinner snack.