Convert from ri [Japan] to league [ancient Celtic]

Unit Definition (ri [Japan])
The ri is a traditional Japanese unit of distance, sometimes called the Japanese league because it is of similar length to the European league. The ri equals 2160 ken or 12 960 shaku (the shaku being the Japanese equivalent of the foot). This is about 3927 meters or 2.44 statute miles.

Unit Definition (league [ancient Celtic])
League is a unit of distance long common in Europe and Latin America, although no longer an official unit in any nation.