We consider the matrix elements of the left-handed flavor-conserving
four-quark operators in the nucleon and pion states. Using chiral symmetry, we
derive relationships among these matrix elements. We argue that the ΔI=1/2 rule of hyperon and kaon non-leptonic weak decay implies possible large
strange-quark content in the nucleon and pion.Comment: 10 pages in Plain TeX, MIT CTP #218