According to Stitt's book Japanese Ceramics of the Last 100 Years Meito went out of business during WWII. However, Kovels states that it was acquired by Narumi during WWII, and continued to use the Meito backstamp.There are Meito with Made in Occupied Japan" marks. The English sites I have seen say the meaning is fine sword which would have these characters 名刀 but I really can't find much in Japanese.
According to "Collector's guide to Made in Japan Ceramics, Book IV" by Carole Bess White, the mark #64 with the Meito China in red above the green crown, Hand Painted Made in Japan is attributed to Nagoya Seito Sho which began business in 1908. The name was changed to Narumi Seito Sho by at least 1934, as her #75 mark is "Narumi China" one. Narumi continued to use the Meito name on some items for some time.
Made for Export
This is a rather common MEITO green mark
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MEITO 明陶 (Not the same Meito as above)
This is not related to the Meito/Narumi as the kanji are different.
