Japanese porcelain

set of 7 teacups with saucer plate, creamer and sugar. Vintage Nippon porcelain, egg shell, gold paint. bought around 1980s Chinatown LA. Very deliquete. I believe it is hand painted because there is some irregularities but there is no seal. It belongs to my mother who has a small collection of chinese and japanese china. We would like to know the value of this tea set.

Thanks