Posture for kendo is called shizentai. It means "natural posture". Without having the good shizentai, your kendo won
The Official Guide for Kendo Instruction, PDF
Building foundations for advanced skills
Beginner's Guide to Kendo
Shisei 姿勢
Beginner's Terminology
Kendo-Guide.Com - Shizentai means natural posture
Kendo Complete Beginners: Shizentai is Natural Posture
Good Posture in Kendo Queen Mary Kendo Club
Shizentai: Natural Posture
Body core and Shinai handling
Welcome to our newest Beginners
[ZERO TO SHODAN] - Kendo for Beginners : Episode 6 - Striking Practice (part 2)
Building foundations for advanced skills
Kendo: Fundamentals and Waza to Win – Budo Books
Kendo Study: How to Keep Your Posture Beautifully Before, During