The Flat Head Medium Weight Thermal Shirt (Black)

Size Guide
These are the standard thermals from The Flat Head which have been popular in Japan over 20 years! 
Created using vintage knitting machines, the fabric is surprisingly not too heavy yet incredibly warm! For added durability, these come with the iconic triple stitched collar and flat seam stitching construction. 
These are perfect for days when you want to keep warm! Wear it under a jacket or sweater and stay cosy!  
  • 100% Cotton
  • Japanese medium weight “waffle” thermal
  • Color is over-dyed (which will age gradually with wears & washes)
  • ‘FH” embroidery on left sleeve
  • Ribb cuffs
  • Once washed 
  • Slim fit
  • Made In Japan
NOTES: The garment will stretch 2'' ~ 2.5’’ bigger in the chest ; 0.75’’ ~ 1’’ bigger in other dimensions with wears. Please consider to buy it in a snug fit.

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How We Measure

Pants and Shorts


With the major buttoned up open the jeans and lay them flat like shown. Measure from the front where the major button closes to the back belt loop. Then double this measurement to achieve the waist measurement.

The way we measure is different from 'Side to Side', If you are not used to our method you should downsize by 1 inch.

For example, side to side measurement for The Flat Head 3002 waist is 28inch and using our method 29.25 inch.

Front Rise:

With the jeans lying flat measure from the crotch bar tack to the top of the waistband. 

Back Rise:

Spread out the crotch so the bar tack is visible, then measure from the crotch to the top of the waistband.


One inch down from the crotch measure flat across to the other side.


Flatten the leg and measure along the inseam from the crotch to the leg hem. 

Leg Openning:

Measure straight across the hem from side to side.



Lay flat then measure from the shoulder's edge to the other shoulder's edge.


Lay shirt flat and measure from pit to pit.

Sleeve length:

With the sleeve flat measure from the shoulder to the cuff.

Arm hole openning:

Measure from the shoulder down to the pitt.

Vertical length:

With the shirt facing down, Measure from below the collar to the bottom hem.