Mars is a shojo manga by Fuyumi Soryo. It explores the romantic relationship between Kira Aso, a shy painter and Rei Kashino, a good-looking delinquent and racer.
Kira Aso and Rei Kashino meet when Rei asks Kira for directions to a local hospital one day in the park, but instead of telling him the directions she draws him a map and hands it to him without saying a word. On the back of the directions is a picture Kira drew of a mother and child. On the first day of school they are both surprised to find that they are in the same class. Later Rei walks in on their teacher sexually harassing Kira. Rei promises to protect Kira in exchange for a painted version of the sketch that was on the back of the map. He also offers to "lend Kira his body" and she asks him to model for her.
Okay, the above was taken from wikipedia and probably accurately summarizes the first volume. But Mars has 15 volumes and a lot more happens. It started out pretty interesting. The character types were new and different. Rei seems carefree and confident but has many terrible secrets and experiences. Kira also has gone through a lot. Their 'inner sadness' is what brings them together, though the causes for them are revealed much, much later in the story. Kira is shy, but not spineless or pushed around. Rei is not like one of those delinquents who have no real reason to be one. He also has his dreams and passion. At no point does their relationship seem forced or one-sided. The guy, though he is a delinquent doesn't push his feelings or himself on Kira. This is quite refreshing since I have read a lot of manga where feelings seem really forced or baseless.
The romance develops slowly but steadily and there are plenty of obstacles along the way for love to overcome. One thing is that the secondary characters are cardboard cutouts and don't really serve any particular purpose other than the girl's/guy's best friend stereotype.
Art is not quite as big a part of the story as one would expect. Racing is given a lot of prominence in the first few volumes, but then as things change, there is hardly any mention of it for a few volumes.
One thing I felt was that the writer tried to project the characters as wounded victims of their families, and uses every possible cliched plot device to suck synpathy out of the reader. It really seems unbelievable at times how so many bad things could have happened to both of them in the past.
Characters- 5 for main, 2 for side
New characters types for shojo
Darker than other shojo manga
Well developed characters and relationship
Some really unnecessary plot elements are added to victimize the characters
Illustrations seemed a bit oldish to me, similar to older manga
Would have liked to see more art
Overall, 15 volumes isn't that long to invest your time and energy into this deep manga.
NOTE- All pictures are from google image search. They are copyright of their respective owners.