Abstract
Although involvement of informational sugar chains has proved essential in extensive biological phenomena, explanations given for understanding the true meaning of sugar recognition are not satisfactory except in a limited number of cases. Comprehension of the peculiar nature of sugar recognition is essential for understanding the true roles of sugar chains in life. This article is intended to give some clue for better understanding of sugar recognition, completely different from recognition of nucleic acids and proteins, on the basis of three key words, non-linear, fuzzy, and weak.
