We deal with the system of functional equations I(x,T(y,z)) = T(I(x,y),I(x,
z)), I(x, I(y,z)) = I(T(x,y),z), where function T: [0,1](2) --> [0,1] is a
strict t-norm and I: [0, 1](2) --> [0,1] is an unknown function. Under some
assumptions imposed on function I we obtain that I is almost conjugate wit
h the Yager fuzzy implication.