Quasi-asymmetry model for square tables with nominal categories

For an R×R square contingency table with nominal categories, the present paper proposes a model which indicates that the absolute values of log odds of the odds ratio for rows i and j and columns j and R to the corresponding symmetric odds ratio for rows j and R and columns i and j are constant for every i<j<R. The model is an extension of the quasi-symmetry model and states a structure of asymmetry of odds ratios. An example is given.