One common theme is friendship. The two Nanas have a very unique bond, and many fanfictions explore how deep that friendship can go. It could be about them supporting each other through tough times in their lives.
The Sachiko Japanese ghost story is often a chilling tale. Usually, it involves elements like an eerie presence. Sachiko might be a spirit with a tragic past that haunts a particular place. In many Japanese ghost stories, there are often themes of vengeance or unresolved issues from the spirit's past life. However, there are different versions of the Sachiko story, some might focus on a specific location she haunts, like an old house or a forest.
One common element is the sense of a tragic past. Sachiko is likely to have had a difficult or unfair life that led to her becoming a ghost. Another element is the idea of a haunting. This means she is associated with a particular place, like an old building or a dark alley. Fear is also a big part of it. People in the story are usually scared of Sachiko's presence, whether it's through seeing her or just feeling her 'energy'.
Another theme could be family acceptance. Their families' reactions to their marriage and how they deal with any potential issues or misunderstandings related to family expectations.
Growth and self - discovery are other themes. The relationship between the two can be a catalyst for each character to learn more about themselves, as they interact and face different situations together in the fanfic stories.
One popular 'nana x nana fanfic' story could be about their adventures in a new city together. They might discover new music and bond over it, exploring the local music scene.
One great place to start looking for Sachiko and Yumi married fanfiction is Archive of Our Own (AO3). It has a large collection of fan works. You can search for the relevant tags like 'Sachiko and Yumi' and'marriage' to find some interesting stories.
One great place to start looking for Sachiko x Yumi fanfic is on fanfiction.net. There are often many different takes on their relationship in the fanfics there.