It's hard for me to think of an equivalent phenomenon in the Western canon—what if developers allowed us to date the historical figures found in Assassin's Creed games?
You play as Chizuru, who disguises herself as a man to travel to the capital of Kyoto in search of her missing father.
She accidentally gets tangled up with the local police, the Shinsengumi, and the story evolves from there. It's a samurai history lesson with a Twilight twist.
Souji Okita will almost always be tragic and tubercular -- if you Google his name, his historical Wikipedia profile will appear alongside art of his Hakuoki incarnation.
Tools like multiple save slots, quick-save features, and the ability to skip text and rewind help players efficiently pursue every potential partner character and reveal every story path.
It’s like backwards-engineering a narrative database -- and you may be surprised to find how much the story changes when you focus on a different partner each time. Hakuoki is a period piece, taking place in the Bakumatsu period of Japan at the time of civil unrest between the Emperor and the Shogun.
Generally you meet several characters, and will have to choose one to court.
In Japan, dating sim characters are referred to as “capturable” -- whether that means you capture their hearts or their bodies depends on the game.