This is an early model haversack with the metal hook used to attach to the waist belt. An example is pictured on page 171-174 of the excellent reference book Heitai by Agustin Saiz. If you like woodwork fresh military items visit my e-bay store and save me as one of your favorite sellers.
The item "WWII Imperial Japanese Army Haversack" is in sale since Tuesday, September 28, 2021. This item is in the category "Collectibles\Militaria\WW II (1939-45)\Original Period Items\Japan\Other Japanese WWII Orig Items". The seller is "military_collectors_services" and is located in Webb City, Missouri. This item can be shipped to United States.