Sang Doo, Let's Go To School (2003)

Both about a poor single father straggling to take care of his kid!

Same female Lead and same writer...with a little cute sick child

...both dramas are about dads who fight for their kids life, both dramas has well made roles and captivating story.

Well, not necesarilly have similar story. But the vibe of sangdoo have similarities with just between lovers. Since it's oldies drama the feeling of poor background of our hero seems more ground and real in sangdoo.

Male Lead and Female Lead are close in their youth but unfortunate events occur to the ML, ruining his life and separating him from the FL. When they are adults, ML goes back to high school as a student where FL becomes one of his teachers.

Written by the same writer, both feature tragic long-term lost loves and main characters who are complex and sometimes dishonest.

Both have the same basic premise with similar characterization: female lead who is a school teacher, engaged to a respectable guy, but both female leads get involved with a not so respectable guy.

The leads are the same. Sang Doo is the first main role for Rain and he acted very well. Rain acted a father who adored his daughter and his love in both dramas. CBM is more hilarious than Sang Doo. They don't have same plots and Rain's character in Sang Doo is more miserable.
Both dramas are must-watch! ;)

its awesome and fabulous.. you must watched this!!