Moon Embracing the Sun

This is more like time travel, where a Joseon Dynasty scholar accidentally transports himself to 21st century into a movie set about Joseon Dynasty & falls in love . It can be considered both historical both modern and includes time travel

A popular teenager inexplicably finds herself in the body of an unpopular classmate - and her body's new owner has no intention of switching back.

The series centers on Ayumi Kohinata, a first-year high school student who has a cute and shy personality. She's excited that she just started dating her first boyfriend, but on the day of their first date, she gets a mysterious call from her classmate Zenko Umine. Zenko says she's going to die, and Ayumi witnesses Zenko jumping from a building. The next thing she knows, Ayumi wakes up in a hospital, but in Zenko's body.

both are about kids that fall in love and are separated because of an "evil" family member (father/grandmother) to meet again after a long time when they got old.. also some young actors are the same (Yeo Jin Goo, Kim So Hyun) and I think both are great dramas with a very sad story :)

Quiet and gentle, Min Jae Yi is everything a good daughter of a prominent family should be. Engaged to the son of the Second State Councillor, Jae Yi knows that the only way to bring herself and her family honor is to accept her fate, which she does with grace and charm. Devoting herself to learning everything she needs to know to become a good wife and mother, Jae Yi dutifully prepares for the future. Sadly, destiny has other plans for her future. Four days before her wedding, Jae Yi’s family is murdered. With no one else to blame for the unexpected tragedy, Jae Yi soon finds herself the object of baseless and horrifying accusations. Blamed for the death of her family, Jae Yi might not have had much of a future at all, if fate hadn’t decided to intervene. Bringing the lonely crown prince, Lee Hwan into her life at just the right moment, Jae Yi is saved from a dismal fate, but her salvation comes at a price. Plagued by a mysterious curse, Lee Hwan agrees to help Jae Yi, but only if she agrees to help him break his curse in return. Unable to refuse such an offer, Jae Yi agrees to the prince’s terms, setting them both on an unexpected path toward love. But what chance does their love have of surviving when one of them is a former murder suspect and the other is a cursed prince?

Yu Jin was raised within the desert tribes of Xiong Nu, although her foster father is a Han. Under certain circumstances, she was forced to flee to Chang'an, the then capital of the Early Han Dynasty, changing her name to Jin Yu along the way. Along her journey, she first meets the calm and kind Mo Xun (aka Jiu Ye, ninth master) and later the handsome, cold general Wei Wu Ji. Jin Yu falls for one of them but is rejected. Will she untangle her love knot? Who will she choose in the end?

Both are historical Korean dramas that have beautiful cinemaphotography and tell a tale of star-crossed lovers. Both also deal with underlining supernatural themes.

In both dramas main leads meet when they are kids and are separated. Again they meet after long time when they are grown ups. Both are great dramas with sad story but KMHM has comedy. Both the dramas are written by same script writer Jin soo-wan, both are having great OST especially theme song.

Two children fated to be together. Where the female protecting the male in their sleep. Jealousy and evil comes along.

Both couples meet when the ML is still a prince, the FL then is assumed to have died and the ML becomes king, shifting into a harder personality. The two then meet again when the FL returns.

Both dramas contain references to the moon, and Yeo Jin Goo stars in both dramas (the ML in Hotel Del Luna and the younger version of Kim Soo Hyun in Moon Embracing the Sun).

It tells both the heart-fluttering love story and fierce obsession of a King with two opposite personalities and an assassin girl who wants to kill him but ends up falling in love with him.

Crown Prince Sajo Hyun is an intellectual character who uses his innate artistic sense to work as a fashion designer at a downtown boutique while hiding his identity of crown prince. He has a wound deep down in his heart from his childhood due to his oppressive father Sajo Seung. Sajo Hyun’s other personality Ak Hee is a charming character who can easily seduce others, but he is cursed to feel extreme pain when he makes physical touch with others.

Yeon Wol lives a life full of twists and turns, going from an assassin to concubine. Yeon Wol is the royal descendant of the fallen Yeon Dynasty and the only daughter of Yeon Poong Hak. Yeon Wol hides her identity and becomes assassin Gye Ra to avenge her family. While trying to assassinate the king, she falls into a trap set by an unknown person and wakes up the next day with no memory of her past.

The Moon that Embraces the Sun is also a historical drama just like Night's Watchman. They both have fantasy as their main genre.
They also involve Shamans. The main lead actress are both shamans.
The main actor in both dramas is a royal. In TMTETS he is a king, while he is a prince in the Night's Watchman.

Now that I think about it Il Woo act in both but in the MTETS, he is the older prince, in NW he is the younger prince.
I just kept being reminded of TMTETS while watching this drama =D

both are romantic historical dramas which emphasize a love triangle between a simple woman, the king of the country and the woman's childhood friend/ the king's brother . Also, a thing which I found very similar was the fact that both stories begin with a childhood sequence of the main characters ^^

It is believed that when a person dies, their soul spends 49 days in Jungcheon, or Purgatory before their eternal fate is decided - heaven, hell or rebirth. That's where accomplished demon hunter Yi Kwak finds himself as he lies on the edge of death in our world. Blessed with astounding swordsmanship and the uncanny ability to see the evil spirits invisible to most, Yi enlisted with the royal squad of elite demon exterminators, the Chuhyongdae, following his fiancee's tragic death. In Jungcheon, he finds Yon Hwa again, but she does not recognize him - she is a spirit of the afterlife now, severed from earthly memories. Moreover, she is deeply entangled in a great war between the white-clad warriors of reincarnation and a swarm of dark spirits determined to forever shatter the cycle of life and death. The battle is desperately close to a terrifying conclusion, so Yi must draw his sword to defend the woman he loves and all they hold dear - and confront the same soul that was once like a father to him.

The storyline is about enduring love from childhood to adolescent, put stop by circumstances. They main lead met again, though initially they did not recognize each other.

Very beautiful Joseon era drama, with great chemistry between the leads.