The tag is Japan size.
Please check the following Japan size to US size conversion chart.
US XXS (JP XS)
Waist: 61 cm, Hip: 110.5 cm, Front rize: 27.5 cm, Inseam: 67 cm
US XS (JP S)
Waist: 64 cm, Hip: 113.5 cm, Front rize: 28 cm, Inseam: 67 cm
US S (JP M)
Waist: 69 cm, Hip: 118.5 cm, Front rize: 28.5 cm, Inseam: 67 cm
US M (JP L)
Waist: 74 cm, Hip: 123.5 cm, Front rize: 29 cm, Inseam: 69 cm
US L (JP XL)
Waist: 79 cm, Hip: 128.5 cm, Front rize: 29.5 cm, Inseam: 71 cm
US XL (JP XXL)
Waist: 85 cm, Hip: 134.5 cm, Front rize: 30.5 cm, Inseam: 71 cm