・マテリアル：　ウールツイルクロス
・ボタン：　U.S.N.アンカー樹脂ボタン

The U.S.N. WOOL BLUE FLANNEL SHIRT is made from wool twill and features authentic U.S.N. urea anchor buttons. Originally issued to Chief Petty Officers in the early 1940s, this single-pocket shirt includes an arched pocket flap and cuffs crafted from identical parts, reflecting wartime design simplifications.

Introduced in the 1920s, the CPO shirt initially had double pockets but was revised to a single-pocket style during World War II, likely as a move to streamline manufacturing. Interestingly, the double-pocket design returned after the war in the late 1940s.

Although not officially part of the peacetime uniform, the shirt could be worn with approval from senior officers, especially in colder weather. Over time, this rule became more flexible and less strictly followed.

Post–World War II, surplus CPO shirts spread to army-navy stores, where they found a new audience beyond the military. Outdoor enthusiasts and tradesmen gravitated toward the heavy wool overshirts. As their popularity spread, the term “CPO shirt” came to describe a wider category of civilian work shirts inspired by the Navy original. Many retained signature features such as flap chest pockets and the classic anchor-stamped buttons, preserving their maritime roots.

• 100% Wool Twill Cloth
• U.S.N. Urea Anchor Buttons
• Single Chest Pocket
• Made in Japan