"I should explain here that the underlying purpose of Judo is to enable a physically weaker person to defend himself against a physically stronger opponent, alike in mimic combat on the mats of the Dojo or exercise hall and in a genuine struggle for survival outside it.
Other things equal it is simply axiomatic to say that the stronger man must eventually win, but seeing that not infrequently the relatively poorer physique of one man is largely offset by his superior intelligence, skill, and agility, he may conceivably prove the victor in contest with his physically more powerful antagonist.
And admitting that there are always numerous gradations of sheer bodily strength among the pupils of any Dojo, the cumulative effect of assiduous study and practice of Judo is bound in the end to convert even a veritable tyro weakling into a physically vigorous and technically skilled Judoka." -- E.J. Harrison, Manual of Judo