Convert from ri [Japan] to span

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 (span)
Span is the width of a human hand, from the tip of the thumb to the tip of the pinky finger.