The word "Nippon" in western characters means " Japan" and occurs on most Japanese wares from around 1890 until the early 1920's.After the McKinley Tariff of 1891, all goods imported into the United States had to be identified with their country of origin ,in western characters. If your piece does not have a country listed, it is possible it dates before the early 1890s. Of course, there are exceptions, so be careful making assumptions! (see McKinley Tarrif)http://en.wikipedia.org/wiki/William_McKinley
Thus Japanese exports (to America) were marked with "Nippon" in English from this date to 1922, when the requirement was changed so that the word "Japan" (English for Nippon) should be used. These are the so-called " Nippon wares". (Some of the finest examples of Japanese ceramics were made during this period). However, the rule doesn't apply in other countries nor always in America because sometimes paper labels and the like were used. So while finding a back stamp saying " Nippon " is a useful dating aid, its absence is not determinative.
There is also the possibility of pieces having both"Hand Painted Nippon" and "Made in Japan"in the same mark.(I even have a Nortake piece which has "Nippon" on it). Some people might place a higher value on these but not everyone.
There are also 'Transitional' marks which are identical to the 'Nippon' marks used previously but now state "Made in Japan". Companies later changed their marks.
Fake Nippon first appeared on the market in the early 1980's. The early reproductions were poorly decorated and had fake back stamps which could easily be differentiated from the authentic back stamps by knowledgeable collectors. However, many novice Nippon collectors were fooled by these pieces and unknowingly added these "fakes" to their collections. Over time the companies making these fake pieces have perfected the M-in-wreath back stamp. It is impossible to tell the authentic back stamp from this new fake! Additionally, other authentic back stamps such as the Maple Leaf and Rising Sun were also being used on fake pieces. While these fake back stamps were slightly different from the authentic back stamps and definitely not as perfect as the M-in-wreath fake back stamp, they could fool collectors.
Recently, thanks to the efforts of the Noritake Company, U.S. Customs has ruled that the fake M-in-wreath mark is counterfeit and not allowed for importation into the United States. Because of this ruling, wholesalers, for the time being, have stopped marking their fake Nippon with the Noritake Company back stamps (including the Maple Leaf, Rising Sun, and RC marks). Fake Nippon is now being sold 'unsigned'; that is, with no back stamp. The items come into the United States with a paper label identifying the country it was made in. Of course, the paper label is easily removed leaving the item 'unsigned.'
In addition to changes in the back stamps, the actual mold style and decoration of the fake Nippon has been improving. In fact some of the newer fakes are being copied from original patterns used during the Nippon era, making them reproductions not fakes. The quality of these reproductions, while much improved over past fakes, is still not quite right and the feel of the porcelain is wrong. However, the overall quality of these reproductions is getting better all of the time and it's imperative for collectors to be aware of this