In August 2012, upon a request from the Thai Ministry of Culture, members of the TNRICP staff conducted an onsite survey of the Japanese lacquer doors that adorn the worship hall of Wat Ratchapradit, built in 1864, which has been designated as a first class Royal Buddhist temple. Samples of the mother-of-pearl and lacquer painting materials were carried to Japan where experimental repair was carried out through a study of the materials and consideration of possible repair methods. The double doors of the inner area of the worship hall are made of 65 pieces of Japanese-made mother-of-pearl on ground color, and 31 pieces of lacquer painting. They are a fascinating standard-setting example of late Edo period, Japanese export-use mother-of-pearl on ground color. The author anticipates that they will further research into 19th-century export lacquer. With thoughts of connections to lacquer doors in mind, the author, Futagami Yoko and Yamashita Yoshihiko, who were involved from the onsite survey for the commissioned research onwards, carried out a “Basic Survey of Late Edo Period Mother-of-Pearl with Ground Color Works,"" thanks to the cooperation of the Nagasaki Museum of History and Culture, the Siebold Memorial Museum, the Kobe City Museum and the Tobacco and Salt Museum. This article presents a revised version of the “Chronology of Export Lacquer with Mother-of-Pearl with Ground Color,” which was presented at the research group meeting held on July 30, 2018 at the TNRICP. In addition the article presents new information gained from the above-mentioned survey, plus relevant historical materials, while also with the aim of positioning the Wat Ratchapradit doors as a benchmark example of export lacquer with mother-of-pearl with ground color. First, we examined plaques and plaquettes that can be dated as a precursor in our consideration of 19th-century mother-of-pearl with ground color. The first example is found on the back surface of a plaque with a design of a landscape in St. Petersburg in maki-e, which was a European-made bronze plate with a lacquer picture fired onto it. The back surface has a floral spray design worked in mother-of-pearl. The Writing Chest with Battle Design in Maki-e and Mother-of-Pearl Inlay is signed Sasaya. There is no ground color found on these works, which were made around the year 1800. Counter to these works, the Plaquette with Portrait of Frederick II is a mother-of-pearl with ground color work thought to correspond to the ""rectangular portrait of Frederick II with mother-of-pearl inlay,"" included on the 1793 collection list of Johan Frederik van Reede tot de Parkeler. Thus it is at this stage that mother-of-pearl with ground color appears. However the next benchmark example of mother-of-pearl with ground color on a colored portrait picture does not appear until the 1830 (Tenpô 1) Snuff Box with Portrait of Philipp Franz von Siebold’s Wife and Daughter in Mother-of-Pearl Inlay. In 1806 the Dutch commissioner Hendrik Doeff was en route to an audience with the shôgun when he saw objects with shell inlay at Aogaiya (shell work shop) in Kyoto and placed an order for such goods. Starting in the 6th month of that year Aogaiya moved to Nagasaki and became a merchant that dealt with the traders on Deshima. While up until around 1800 export lacquer wares consisted largely of planar items such as plaques, plaquettes and pen cases, or large-scale items such as furniture, an order list sent to the shell inlay merchant in 1814 indicates that with the new participation of the shell inlay merchant, there was then a shift to a richer variety of small items. Next we investigated works from European collections, namely the Paint Box with Design of Landscape, Birds and Flowers in Maki-e and Mother-of-Pearl Inlay that corresponds to no. 448 in the collection catalogue of Jan Cock Blomhoff (1779-1853) who was both warehouse manager and trading commissioner on Deshima, and the Snuff Box with Portrait of Johann Bartholomäus von Siebold in Mother-of-Pearl Inlay, a work with the portrait made in mother-of-pearl with ground color worked solely in silver leaf and ink lines, found amongst the Philipp Franz von Siebold (1796-1866) materials. These works, along with the Tobacco Box with Design of Venus and l'Amour in Maki-e and Mother-of-Pearl Inlay, can be positioned as early examples of mother-of-pearl inlay with ground color. Nagasaki trade declined in the Tenpô era (1830-44) and this meant Aogaiya similarly went through difficulties. But then in 1840 (Tenpô 11), they participated in an attendance on the shôgun by Nagasaki businessmen. It was the general rule at the time that Kyoto was the center of export lacquer production, but then real power shifted to Nagasaki merchants and at some point this meant a shift of export lacquer production locale from Kyoto to Nagasaki. In 1848 (Kaei 1), we can see that Nagasaki merchants other than lacquer merchants also began to use mother-of-pearl decoration and that Nagasaki-made mother-of-pearl with ground color wares were being exported via Chinese merchants. We can thus determine that it was the presence of Chinese merchants that aided the export of such works to Thailand. However, given the imagery in the door's lacquer paintings, the Wagôjin image by Nagasaki painter Ishizaki Yûsai (1810-62) and the presence of the Kurokawa family who did lacquer painting, it is highly likely that the lacquer door paintings in Thailand were made in Nagasaki. Judging from information on the activities of the export lacquerware merchants in Nagasaki and lacquer paintings, the author believes that a newly invigorated Nagasaki merchant was connected to the Wat Ratchapradit lacquer doors. Prior to these studies the Aogai maki-e hinagata hikae (Miniature Design Book for Furniture in Maki-e and Mother-of-Pearl Inlay) and Nurimono hinagata hikae (Miniature Design Book for Furniture in Maki-e and Mother-of-Pearl Inlay) have been considered the two basic texts on Nagasaki-produced mother-of-pearl with ground color. While these books with hinagata, literally miniature, in their titles mean that these books are materials related to set shapes and sizes they cannot be considered fundamental materials for mother-of-pearl with ground color works. The Wat Ratchapradit door materials provide an opportunity for comparing materials and techniques in mother-of-pearl with ground color works, and allow a tightening of production time frames for mother-of-pearl with ground color works which have previously only had a relatively broad chronological framework. These materials are also important given their reflection of the characteristics of Nagasaki-produced mother-of-pearl with ground color. Through a study of the door materials at Wat Nang Chi and the Japanese-made lacquer items in the Thai royal household, we can begin to see a new aspect of 19th-century Nagasaki trade.