Pair Ryōma Sakamoto Ceramic Cups 3.75" Tall White & Blue Samurai

Pair of ceramic cups with an image of Ryōma Sakamoto (spelled Ryouma on the cups) who was a Japanese Samurai. Each cup measures approximately 3.75" tall. They are marked on the bottom but I can't find any information on the mark or the age of the items. No chips or cracks noted. See pictures for further details on condition.