phew good question, at the beginning i had the same prob. I shaved my hair for 5 jears so i thougt i have 1, but after some month i saw i have more something between 1 and 1b.

Hm do you have a brother ore sister? recently i realiced my brother as exact the same hair colour like me. The other way is to colour your hair like the piece if it does not match. And the last method is you send john a photo from your hair, but that could be not exact. But better than nothin for some month