way of the sword; swordsmanship
Refers to the philosophical and practical path of swordsmanship, often associated with martial arts traditions such as kendo. The cross-reference to 道 (みち) sense 8 suggests a meaning akin to 'the way' or 'path' as a discipline.
See also: 道 (みち)
He trains every day to master the way of the sword.
Compound of 剣 (けん, 'sword') + の (possessive particle) + 道 (みち, 'way, path'). The phrase follows the pattern of other traditional 'ways' (道) such as 茶道 (sadō) and 書道 (shodō).