Vintage iridescent lustre ware teacup trio

Hello from Christchurch! I found this pretty trio with an unidentified potter's mark. From the design, I have strong suspicions that this is Japanese after comparing with many images online although the MIL thinks it's European. Any help would be appreciated, I went to gotheborg.com but was unable to find it. Will try to post on another pottery website as well.

I have lots of vintage treasures which I will be posting, I know I have been on a hiatus for a while but I have found some goodies this holiday!