Is there an expiration date for Murasaki Koubou Soap?

Due to the absence of preservatives and antioxidants used in production the expiration date is 6 months from the date of manufacture.
We manage the production so that the soap is aged about 2-3 months when it arrives to your hands.

The surface color is whitish. Is this an issue?

The surface is whitish due to oxidation as it touches the air, but this is natural and there is no problem with quality.

What are the blue grains in a soap?

These are power particles of Shikon. Please be assured that it is not a foreign substance.

What should I do with a rinse or conditioner after washing my hair with the soap?

It depends on the length and condition of your hair as well as the frequency and duration of use.
If you are concerned about the coarseness of your hair, please use your current rinse or conditioner after rinsing this soap.