Odd- J pairing in nuclei

We point out a simplicity that arises when we use an interaction in which only an energy with odd J is non-zero. The emphasis is on J= J_{max} and in particular J=9+ in the g_{9/2} shell. It is noted that high overlaps can be deceptive. In many cases a single set of U9-j coefficients gives either an exact or a very good approximation to the wave function of a yrast state.