The Ingo rating system was developed by Anton Hoesslinger in the late 1940's and published in the periodical Bayerische Schacht. The system is named for the location Ingolstadt Germany. In this system, lower numeric rating indicate stronger players.
The rating formula is R = O - ( W - 50 ) where:
R is the players new rating, O is the arithmetic average of the ratings of the player's opponents, and W is the player's win ratio express as a percentage.
Ingo bears some similiarity to the system created by the BCF