The tag is Japan size. US size is for reference only.
Refer to the following measurements.
US XS (JP S)
Length: 69 cm, Shoulder width: 46.4 cm, Chest: 114.2 cm, Sleeve length: 26.8 cm, Neck: 44 cm
US S (JP M)
Length: 71 cm, Shoulder width: 47.9 cm, Chest: 119.2 cm, Sleeve length: 27.6 cm, Neck: 45.5 cm
US M (JP L)
Length: 73 cm, Shoulder width: 49.4 cm, Chest: 124.2 cm, Sleeve length: 28.3 cm, Neck: 47 cm
US L (JP XL)
Length: 75 cm, Shoulder width: 51.4 cm, Chest: 132.2 cm, Sleeve length: 28.8 cm, Neck: 49 cm