Honnouji ni Moeyu Sengoku Ichi no Himegimi ni Tensei shita Ippan Mobuko wa, Oshi Bushou no Chouai wo Yorokobenai

"Maybe now that I'm Oichi, I can get my favorite ship, Mitsuhide and Nobunaga together!?"

Fujiyoshi Ichiko, a 30-something office worker and fujoshi who adores the Mitsuhide x Nobunaga pairing, collapses from overwork while playing a history game. When she wakes up, she finds herself in the game's Sengoku period, reincarnated as Nobunaga's sister, Oichi.

Ichiko is thrilled to be so close to her favorite pairing, Mitsuhide and Nobunaga, but in the near future, they will kill each other in the Honnoji Incident. So Ichiko uses her knowledge of the game and history to try and prevent the Honnoji Incident, but for some reason, handsome warlords keep vying for her affections...?

(Source: Kadokawa, translated)