Formation of Judo Canon wasn’t a single-time effort. Many techniques that gave Judo upper-hand in 1880th Police Budojutsu contest never made it in. Anyway, who needs a canon in the first place? Why to say that some technique that works (“technique” that doesn’t works isn’t a technique to begin with) not good enough to enter into canon when other are just making it in? Isn’t true combat system (and Kodokan Judo is a true combat system by all measures) has no “rules”? Isn’t old jujutsu that formed Judo foundation was all-inclusive? Isn’t it’s no such thing as a “wrong way” to win a fight for your life?
The answer to those questions (if we’ll leave aside subtle semantic and ethical-philosophical connotations) is “yes, it’s no wrong way to win”. So, why the Canon?
The first thing to understand about Judo Canon is that it’s just an element of overall Judo training system.
Judo technical diversity is going well behind Canon and Judo formal techniques. One of the most common and most profound errors of many modern western judokas is identifying and, therefore, limiting Judo to its formal written definition.
As Kodokan assembled multiple schools of jujutsu under its single banner in 1905, the need for Judo Cannon was derived from (1) need to unify Judo in front of the outside world, (2) define training curriculum, and (3) to provide templates for demonstration of primary Judo principals (such as methods of dis-balancing, use minimal of effort for maximum effect, etc.). As Judo became a sport, and especially as it strived for inclusion into Summer Olympics, the need to define clear and easily understood tournament’s rules became the additional reason for defining clear-cut Canon.
Those techniques form modern Judo foundation. However, no technique ever used as-is. Each technique is indeed just a root template that works as a starting point for technical personalization.