It has been awhile since I gave a score of 10 for a manga.
Tateno Makoto's Yellow is indeed a masterpiece.
The first chapter got me hooked that I continued reading it til the end for a whole day. Every chapter is a must read.
Taki and Goh are not your typical uke/seme action couple (where one is weak and often needs a saviour and the other will just appear and be his knight in shining armor )both of them are on equal grounds, both are good looking and they both have good fighting skills (to beat up the bad guys -_^).
They started as partners and their relationship developed as they spend more time together.
Each character has a story of their own. Goh is openly gay, he flirts and sleeps with other men (part of his job), he often makes a lot of advances towards Taki but doesn't succeed.
Taki on the other hand is straight, and just like any other guy, he likes women, he was hesitant to accept Goh's feelings at first but finally gave in in the end
BOTTOMLINE IS.... I might end up spoiling you guys so better read the manga, its A MUST, I'm happy sequels are coming out, can't get enough of those two.