Sky of Love (2007)

-They both feature a bittersweet friendship between a loner or something with someone dying
-They are both very sad and such tearjerkers

Both great and sometimes sad love stories that are extremely touching.

Takabayashi Matsuri learns that she only has 10 years to live due to an incurable disease. She decides to not dwell on her life and not to fall in love, but she meets Manabe Kazuto at a school reunion.

~~ Adapted from the novel "Yomei 10 Nen" by Kosaka Ruka

Both dramas deal with characters with terminal illness and tragic love. Both of the characters lied to their lovers to hide their illness.

Well i havent seen both movies yet, but i have read both mangas, Both are about painfull love, both start at highschool, the have something to do withdeath, it gives you the same feelling

Both is about tragic love and hope. You will cry so much, so be prepared. On many many many tears. Beautiful movies! :')

Both movies are about a high school relationship starting off through text messages. Another similarity is that one half is suffering from a terminal illness while not letting the other person know.

Both are touching but beautiful love stories and both makes you cry a river over them. Both are school romance, but as you can see in Koizora they are not the fun kind of romance, they include "heavy romance". Kou Kou Kyoushi was even heavier. In my opinion, Kou Kou Kyoushi was unforgettable and better than Koizora. So you should see it before you die.

Adiantum Blue is about a pianist with a terminal illness, who wishes to spend her last happy days with her lover in Nice.

Both of them have main characters with a disease they can't cure
Sad endings on both
Love story for the characters
Up and down rollercoaster of emotions

you will understand by the end of the movie. I was looking for this movie like forever and I kept thinking that it reminded me of koizora in some ways

An elementary school teacher named Takano Takayuki who is gradually losing his ability to see tries to hide this fact from his girlfriend Yoko. She eventually discovers the truth and immediately flies home from Mongolia to to comfort him.

Same story except this time the girl's is the one with the illness...
Very touching :')

A summer hit in HK, this romantic fantasy from Jingle Ma is shamelessly manipulative, incredibly cheesy, and totally sappy. It goes to extreme lengths to yank your chains and push your buttons...and it works. Amazingly, this manufactured piece of sap is also an entertaining, compelling movie. An HK version of Ghost and Always, Fly Me to Polaris stars Richie Ren as Onion, a blind-mute who’s in love with his nurse Autumn (Cecilia Cheung). Before any feelings can be exchanged, he dies in a Meet Joe Black kinda way and proceeds to win a celestial contest. This flimsy plot device states he can have one wish - which he uses to live again. They deny him that, but give him the opportunity to return for one week.

Both are touching but beautiful love stories and both makes you cry a river over them. Both are school romance, but as you can see in Sky of Love/Koizora they are not the fun kind of romance, they include "heavy romance". Majo no Jouken was even heavier. In my opinion, Majo no Jouken was unforgettable and better than Koizora/Sky of Love. So you should see it!