Historical Yaoi

Jayeon is sent as a peace offering to marry Heuk, but secretly he replaced his twin sister and he's supposed to marry Heuk. Heuk feels bad for the poor child sent to marry him and treats him kindly, and the two end up wanting to stay together, though Heuk still doesn't know Jayeon's secret.
Trigger warning: abuse, child bride.

In ancient Japan, childhood friends are symbolically married in a "binding ceremony," the lower class one has no idea why and his upper class counterpart is not easy to understand.
Trigger warnings: dubcon, drunk sex, attempted murder.

Ch.1 - a young nobleman hires a prostitute every night to play music for him, and the prostitute falls for him despite knowing the nobleman is still in love with another prostitute.

Ch.4 - includes several stories, but I liked The King and the Potion, about a young king who buys a young boy prostitute out of the brothel and when the two are separated by his scheming officials, the king nearly wastes away until the boy comes back to save him.
Trigger warnings: sex work, attempted murder.

Vol.2 Ch.1-5.5 - In Heian era Japan, Nanami has started a business that steals customers from the local onmyoji using confusion due to its similar name, and Takaichiho is the general who is supposed to get him to change the name. They quickly forget about that though and get into all kinds of ghost and supernatural related shenanigans. Absolute wacky madness up in here. Also mpreg.
Trigger warning: dubcon.

Ch.1-4 contain the stories of two ninja couples in or around warring states era Japan. The first has the man in charge helping get a new ninja ready for a seduction mission, but they fall in love. The second has partners reevaluating what's really most important.
Trigger warning: feels like statutory rape (first couple)

In warring states era Japan, a ninja falls for a guy who helped him and stalks him. The guy is super chill about it once he finds out.
Trigger warning: stalking, drug(aphrodisiac).

Ninja switches sides, joins a man he was supposed to kill who now keeps trying to seduce him, though the ninja is very embarrassed. Smutty with a fun historical setting.
Trigger warning: dubcon.

In Meiji era Japan, a young man begs to be trained by a master samurai, but secretly, he's there to avenge his father the samurai murdered. But can he get his revenge before falling in love? No.
Trigger warnings: lying/manipulation, cheating, betrayal, violence/gore.

In 1940s Japan, a young heir is desperate to see his childhood friend dance again and goes undercover as a worker.

Aoi and Takahiko were best friends, and when Takahiko was enlisted in WWII, they spent one meaningful night together before he was deployed. But after four years with no contact, Aoi is starting to lose hope Takahiko will ever return, until one day he appears way too casually with no explanation for where he's been in the three years since the war ended. A really beautiful and well told story that deals with the scars of war.
Trigger warnings: wartime violence and gore.