<p>This study investigates price determination methods of kimono fabric dealers in early modern Japan, conducting a case study of Naraya, a Kyoto-based merchant that had branches in the Kantō region (Edo and its neighboring areas). In order to cope with data availability limitations, the investigation utilizes historical records of other major Kyoto-based merchants with Edo branches and those of modern times as well. There were two price determination methods: namely, the “uchi-mashi” and “soto-mashi” methods.</p><p>Uchi-mashi: Cost ÷ (1 - (Profit percentage ÷ 100)) = Selling price</p><p>Soto-mashi: Cost × (1 + (Profit percentage ÷ 100)) = Selling price</p><p>Naraya used the uchi-mashi method for “kudari mono [kimono fabrics purchased in Kyoto and sent down to the Kantō region].” With regard to “kantō mono [kimono fabrics purchased in the Kantō region],” the soto-mashi method was adopted. There were three pre-determined profit rates applied in the calculation, corresponding to three different categories into which commodities were classified. In the case of kudari mono, however, it was a common practice that prices were increased higher than calculated selling prices depending on the quality of fabrics and popularity of their designs. In addition, there were unique business practices concerning price tags. When commodities were sent from Kyoto, prices were doubled, and such doubled prices were written on price tags. “Cash only, price on the tag” sales were also held. In introducing these practices, Naraya followed precedents of major merchants that had branches in Edo. This is the first Japanese economic history study that gives an in-depth analysis of early modern merchants’ actual business practices concerning price determination.</p>