Looking around Mito City in Ibaraki, I see:
Iijimacho (飯島町) Mito, Ibaraki 311-4155
and
Iitomicho (飯富町) Mito, Ibaraki 311-4206
but no "Ichimatsu". I could have missed Ichimatsu--it could be there--but I also wonder if your spelling (pronunciation?) of Ichimatsu might be a little off, since those other two are kind of close.
In spite of that, Ichimatsu does sound like it should/could be a place name here.
Good luck!