When I registered my inkan (as jitsu-in; official personal seal) back in 2009, the rules at the Minato-ku ward office were that it had to contain only the lette

When I registered my inkan (as jitsu-in; official personal seal) back in 2009, the rules at the Minato-ku ward office were that it had to contain only the letters of my name, which I imagine is the general rule. I imagine you could use this more as one of the less formal seals like the mitome-in.