Blue Birthday (2021)

Lovely Runner and Blue Birthday (2021)are both South Korean dramas that delve into the themes of time travel and the complexities of human relationships.
Similarities:
Time Travel: Both dramas involve characters who have the ability to travel back in time, often to rectify past mistakes or understand the circumstances surrounding a loved one's death.
Romance: Both series feature central romantic relationships that are deeply affected by the time travel elements.

In blue birth day drama ,The mystery surrounding the deceased first love in Blue Birthday keeps viewers guessing and invested in the story.The characters in Blue Birthday are often seen as complex and relatable, allowing viewers to connect with their struggles and triumphs than lovely runner.

Blue Birthday stands out for its intriguing premise involving time travel and mystery. The story revolves around a woman who uses mysterious photographs to travel back in time to try and save her boyfriend's life. This concept provides a captivating framework for exploring themes of love, loss, and the complexities of fate.

Time Travel: Both series involve the protagonists traveling back in time to revisit their past. In A Time Called You, the female lead travels back to 1998, while in Blue Birthday, the female lead travels back to her high school days.  
Lost Love: Both series explore the themes of lost love and the desire to change the past to prevent tragedy. The protagonists in both dramas are deeply affected by the loss of loved ones and seek to alter their fate.
Romance: Both series feature romantic elements, with the protagonists developing strong emotional connections with characters from their past.
Mystery: Both dramas incorporate elements of mystery as the protagonists try to uncover the truth about their past and the circumstances surrounding their loved ones' deaths.

The two travel to meet an old love............................................................................................................................

Blue Birthday (2023) is inspired by the Korean Drama that goes by the same name, Blue Birthday (2021)

Same everything just a series of 16 episodes.Where the female lead travels back in time burning a photo to save the male main lead . But she did not know it came with a price.

Both are similar in a way that female leads tried to help their crush live. Both shows also have the same time travel troupe but different in medium. For example, Blue Birthday works with photos while Orange depends on letters. Blue Birthday is more on the thriller side while Orange is more on the romance, youth side. Both are equally good in executing the show.

In both dramas you travel to the past through photographs in order to conquer your 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 the protagonists are afflicted because years ago they failed to save what was their first love.

Both dramas are mystery dramas that have the concept of going back in time to find the solution to a crime/ change the outcome of a event that already happened. On Reset the main leads are stuck in a time loop, while in blue birthday the main leads (inicially only the FL) can go back to a specific time window based on photos.

The leads travel back to the past in both dramas (although for separate reasons and through different means i.e. photographs in blue birthday and cell phone in first love again)

Here at first it is revealed that FL gets to time travel where she can reset everything that she regrets even if she needs to sacrifice herself too
This drama one of the bestest dramas that keeps you on edge and also ending will definitely make you feel glad
I felt good while watching it

Both dramas deal with time travel / time slip.
Manhole(2017) - Male main lead Bong Pil time travels into the past through a manhole in an effort to stop the wedding of his lifelong crush, Soo Jin, set to happen one week into the future. whereas in
Blue Birthday (2021) - Female main lead Oh Ha Rin will revisit the past through mysterious photos left by her first love, Ji Seo Jun, who died on her birthday 10 years ago, and prevent his death. (for every time travel the person needs to pay a price )

It's the same as blue birthday. It has time travel content. Travel through time to save someone. And also fix love.

On her 17th birthday, Ozaki Karin suddenly lost her childhood friend and first love, Soma Jun. Ten years later, on her 27th birthday, Karin happens to find a film camera left behind by Jun and the photos he took of her. This causes her to remember all the feelings she had for Jun. Unable to control her emotions, Karin burns all the photos and is transported back in time to the day the photo was taken 10 years ago. As Karin travels back and forth between the past and present to stop Jun's suicide, she slowly discovers the shocking truth behind her childhood friend's death.