Iron Heart IHSH-442 SAX Blu Review — 9oz Selvedge Flannel Check Work Shirt

If you know Iron Heart, you know their Ultra Heavy Flannel shirts — the 12oz and 14oz monsters built for winter. The IHSH-442 SAX takes a different approach. At 9oz, it's Iron Heart's lighter-weight flannel offering, designed as a breathable alternative for warmer months without sacrificing the craftsmanship and Japanese manufacturing the brand is known for.

The sax blue colourway is no accident. It's a direct nod to Iron Heart's sought-after 20th anniversary UHF from 2022 — a classic sax blue check that proved so popular it became the blueprint for this season's 9oz version. If you missed the anniversary shirt, this is your second chance in a more versatile weight.

Fabric

The IHSH-442 is made from 9oz Japanese selvedge flannel — 100% cotton, woven at one of Japan's specialist mills on one of only 4 remaining mills capable of producing these intricate check patterns by switching the weft yarn mid-weave.

Key fabric details:

100% cotton
Unbrushed heel weave
Reactive-dyed warp and weft yarns — no fading to be expected
Placket, cuffs, and gusset in selvedge ID

Care: Wash at 30°C with a low or no spin cycle. Hang dry, do not tumble dry.

Cut & Construction

The IHSH-442 follows Iron Heart's standard work shirt cut — regular fit, not boxy but with enough room to layer over a tee comfortably.

Construction details:

Work shirt pattern
Regular fit
Button fastenings (4-hole)
Chest pockets with pen holder
Bar tack pocket reinforcements
Straight back yoke
Rounded hem with gussets and chainstitch run-off
Single and double needle stitching
Bar-tack thread for enhanced strength
Chainstitch side seams
Felted internal seams

The construction spec is full Iron Heart — chainstitch throughout, felted internal seams, bar-tack reinforcements at stress points. This is not a fashion flannel. It's built to the same standard as their heavyweight pieces.

Designed by Shinichi Haraki. Handmade by WORKS INC. in Japan.