That’s a Japanese ‘Ei’ mark (in Chinese: “Yong”, meaning eternity) for Ei Sei Sha produced porcelain. Ei Sei Sha was established in 1877 (Meiji period) in Himeji by Matsumura Tokimasa (松村ときまさ) who was born in 1838 in Hizen Arita Saga Prefecture.
Unfortunately, you can’t precisely date pieces from that mark… only guess from the style and quality of decoration or an artist's signature somewhere. The Meiji period ended on 30th July 1912 but the mark was still in use until at least the mid 20th Century. From the painting style, I would guess they're early 20th Century, rather than late 19th Century.