what is or are the saddest kdramas that made you cry the most? 

Remember
That was the only drama where i cried,
I recommend Remember to all of you !
Battle of Changsha. Based on the Japanese-occupation of China during the 1930s. Heartbreaking but very realistic drama.
49 Days
My Rosy Life
I'm Sorry, I Love You
A Love To Kill
I usually stay away from very sad dramas. I remember crying a lot with 'Iljimae' during the first couple of episodes. Another really sad but beautiful drama is 'Marriage Contract'. 
Stairway to Heaven
Mother, its not from Korea but from Japan
I'm Sorry i love you will hold the number 1 spot for me
Tree of heaven
49 Days
1 Litre of Tears,    for me at least i literally cried at least 1 litres of tears, if not more, watching this.
If you haven't cried in every episode after episode 2 then something is wrong with you, in my opinion at least.
It is also a very good Japanese drama to watch, highly rated, good actors with good if not great acting and the plot is amazing.
I honestly can't watch it again because it was that good if not great since it was that sad to watch, if you get what i mean?
1 Litre of tears, Sad love story, Winter sonata 
@Sara - Same!! The only drama that made me cry was "Remember." I haven't finished it yet, but I should. It's so heartbreaking.
as a fan of sad dramas my ultimate sad drama is Japanese 1 litre of tears they lied i cried more than that literally cried like a baby specially that its base on a true  story ,after that i recommend Secret
I don't watch too many sad dramas in general but 1 litre of tears---altho it's a jdrama---holds my number one spot followed by 49 days. I also cried buckets as I watched the kdrama special old farewell.