Sanpō yoshi means good for three sides: good for the seller, good for the buyer, and good for society. It is used to describe the business spirit of the Ōmi merchants.
The phrase itself is modern. The Ōmi merchant scholar Ogura Eiichirō used it around 1988 to sum up their spirit. Its usual precursor is a testament written in 1754 by the Ōmi merchant Nakamura Jihei Sōgan, but the four characters do not appear in it. An earlier use of the phrase is found in a document from 1930.