The word Nippon means Japan in  the Japanese language.  But this doesn't mean that decorative arts, porcelain and pottery that are marked "Made in Japan:" can be called  NIPPON.  Nippon and Made in Japan are not synonymous.Many sellers describe their "Made in Japan " pieces as Nippon. This is a misuse of the term.

True "NIPPON"  was manufactured from 1891-1921, and are marked "Nippon" or "Handpainted Nippon" along with the individual manufacturers mark.  You may find ,as in all of these arts, some pieces are completely unmarked , this is when collectors need to be consulted to determine maker and age.

 The EARLIEST "Made in Japan" era  is from about 1921-1946.  The US determined that imports from Japan would no longer use  "NIPPON"  but would mark all imports with "Made in Japan" or just "Japan", along with manufacturers marks or stickers. These pieces are not considered or should they be described as Nippon.

"Made in Occupied Japan" is the next era of Japanese porcelain and pottery imports. During the US Occupation of Japan the imports  were marked as such. This occured from Sept, 1947-April 1952. This makes dating these pieces relatively easy.

We are now in the SECOND  "Made in Japan",  "Japan"era. All these pieces are described as Post war pieces, from 1952-present. Manufacturers stickers are much more common in this period.

Occasionally,  during this time some marks might include  both "Japan" and "Nippon" . Generally this is due to  a savy manufacturer that was aware of collectors looking for "Nippon " pieces and as a rule these  would not be considered  true "Nippon". Generally, these pieces were  manufactured in the post war  period.  Which is also the period most fraught with counterfeit, fraudulent "NIPPON" pieces.

Some  collectors have tried  to determine if the marks :  "Made in Japan" and just "Japan"  correlate to certain dates, but from my research there is no way to date a piece based on these two  different marks. They interchanged both  of these marks during  both the earlier and the current  "Made in Japan"eras.

So, in conclusion "Nippon" describes a specific era of  manufacturing of Japanese decorative arts, porcelain and pottery.

Next, determining a fraudulent, or fake "Nippon."