In old days, a time when KIMONOs were the only choice for clothing, there was no custom to wear accessories, such as rings nor earrings, let alone pierced earrings, and it's still a commonsense among elderly people.
At that time, the only item allowed was hair ornaments such as combs or hair sticks called KANZASHI. For formal occasions, even wearing OBIDOME (OBI belt ornament) was regarded as impolite, unless it was made of certain kinds of precious stones, such as pearls or jades.
Thus, it's safer for us to learn: accessories are only for casual KIMONOs... For casual KIMONOs, any accessories like rings, earrings, pierced earrings, or even wrist watches, are OK.
This can be an old custom by now, but MAIKOs and GEIKOs were not allowed to wear wrist watches while they were still new, even for casual occasions. Wearing a watch meant that the MAIKO or GEIKO has a steady boyfriend.
Click here to see a blog by Former MAIKO