Recommendations

Both are about a person time traveling to a very different era - one is past to future, the other future to past.

Both are about a modern day FL who travels into the past and finds herself in a love triangle involving at least one prince.

Both are about the younger FL falling in love with the slightly older ML who is her brother's best friend.

In both dramas the protagonists are afflicted because years ago they failed to save what was their first love.

In both dramas there are time travel to be able to save and win the first love.
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In both dramas you travel to the past through photographs in order to conquer your first love........

In both dramas you travel to the past through photographs in order to conquer your first love.......

In both dramas you travel 10 years into the past to meet your first love again...........................................

- seoul man goes to the countryside because of his grandparent
- seoul man has a misunderstaning with his local love interest at first
- drama takes place in a small rural village, where everyone knows each other
- both are cute romances
- both are short dramas

In both dramas there is time travel: in Blue Birthday by burning a photo, in Nine by burning a stick of joss.

Both are historical dramas in which the couple are in an arranged marriage that grows into love. Both FLs run cosmetic shops.

Both are historical dramas in which the couple are in an arranged marriage that grows into love. Both FLs run cosmetic shops.

Both are historical dramas in which the couple are in an arranged or contract relationship. Both FLs run cosmetic shops.

Both are historical dramas in which the couple start out as a platonic relationship (arranged marriage vs. contract relationship) for the sake of the families, and then slowly fall in love. One of the leads runs a cosmetics shop and deals with various challenges with customers.

They are both about a grandfather trying to force his grandson into an arranged marriage,
In BP the Ml and FL enter into a contract relationship to fool the grandfather so he will stop making the male lead go on dates.
In 1% it is the grandfather that specifies that the male lead and female lead get together because the female lead was nice to the grandfather .