The mark is Chinese, which reads "Yangxian Fanggu" and means "imitating the old from Yangxian". Yangxian is the ancient name of Yixing, and is often used in many marks to convey a "more literate or classy feel", especially for zisha teapot. Your source's reading of the mark is correct, it is, however, a Japanese pronunciation of the Kanji. In one of the replies, the continuous scroll enclosing the writings is indeed used in both old and present pots. This is a vintage pot, perhaps from the 90s, the mark is used by the Yixing Pottery Cultural Garden, a pretty large company. They have a lot of employees, some are master craftsman but they only work on the high value products such as handcrafted teapots. Just checked the internet, the tour organized by the recent WBFF convention in China included a visit to this company's factory.
