Similar childhood connection, in both dramas the ML is a doctor and he fell for the FL as a chubby boy.

Both dramas follow a teenager from a rural setting, as she grows up and becomes a woman.
In both dramas the heroine has a past hurt she needs to get over as she finds out who she wants to be and what she wants to do with her life.
Both dramas focus heavily on friends and family.

Although Go East is more comedic, both sramas are about two sets of couples solving cases, with one couple doing all the fighting and the other couple doing all the thinking.

Both are historical asadoras with strong women leads who have to fight for their chosen careers.
Both span a few decades and focus on a few generations of a family.
Both have strong female friendships that stand the test of social standing, time and lifes hardships.
Both have WW2 as a big turning point and they don't sugar coat the harsh reality of the time, while leaving the viewers hope for the future.

Both are a slow paced slice of life taking place mostly in the kitchen.
Nagatan to Aoto: Ichika no Ryourijou has more romance, but in both of them, the focus is on character growth and not love.

A slightly similar premise with a top doctor who has turned into a nurse aide because of trauma.
Both have a mystery, hospital politics and a bit of romance, but Unmet is much more serious.

Same cute vibe and a romantic mixup in high school.
They are both full of secondhand embarrassment humour, and both dramas will have you rooting for the accident prone lead.
Both dramas have an opposites attract scenario.

Same writer, same leisurely pace and focus on beautiful couples eating together in equally beautiful postcard settings. For some viewers it's relaxing, for others it's boring.

Both romcoms have the same funny dynamics between a cold and arrogant boss and his warm assistant.
Only difference is the slight supernatural twist in Masters Sun.

Both have action, a mystery and two hotties going from bickering to jumping each others bones, with love of 18+ moments between them. The Sign has a bit of a supernatural twist, but they still feel similar.

Both have a seemingly age gap between a grown man and an high-school girl, but somehow both dramas manage to be safe and fluffy. Both dramas are funny and full of banter, with the girl giving as good as she gets.

While different in tone and approach, both dramas deal with age gap romance in a sweet and mature way. They address it respectfully, but they both see the lead couple as having personality traits that go beyond their biological age.