The Iron Heart IH-634S-SB Superblack Non-Fade in 21oz Japanese selvedge denim is available at Rugged Gentlemen Shoppe with fast local shipping and easy returns. Due to limited production, certain sizes can be hard to find once they sell through. If your size is currently available, it may be worth securing it while stock lasts.

Our traditional straight cut, medium-rise jeans, made from 21oz “Superblack" selvedge denim. If a stealth look is your thing, this is the denim for you. Both the warp and weft yarns are reactive dyed — far more colourfast than our sulphur-dyed fabrics — designed to retain their deep black hue through wear and washing. Utilising a double-twisted weft yarn and lower tension weave, our 21oz denim fabrics are heavy and tough, yet soft and breathable — creating a pair of jeans that mould to the wearer’s body shape like no other.

Our Fabric Notes

Iron Heart’s 21oz signature denim is known for its dense weave and substantial weight. It feels rigid when new and requires a break-in period, softening gradually with wear. Over time, it develops strong, high-contrast fading.

Our Fit Notes

The 634 is Iron Heart’s classic straight cut, offering a mid rise and an even fit through the leg. It provides more room than the 555 and 666, making it a reliable reference point for those new to the brand.

Who This Is For

Best for those who prefer a traditional straight-leg fit and a balanced, all-around silhouette. Best for experienced denim wearers or those specifically seeking the heavyweight Iron Heart experience.

Made In Japan

• Designed by Shinichi Haraki, handmade by WORKS INC. in Japan

634 Straight Cut

• Traditional straight cut, inspired by the 1966 Levi’s 501
• Medium Rise
• Straight leg profile with a slight taper from knee to hem
• Wider leg opening to accommodate most types of boots and footwear
• Classic 5-pocket design

21oz Japanese Selvedge Superblack Denim

• 100% cotton
• Woven with a double twisted weft yarn
• Right-hand twill weave
• Black reactive-dyed warp and weft
• Fade-resistant to ensure a steadfast colour

Hardware & Construction

• Traditional 3-button fly
• Iron Heart branded tack button at waistband
• Works Inc branded pocket rivets
• Hidden rivets on rear pockets
• Poly/cotton stitching for increased strength
• Single and double needle chain stitch construction
• Belt loops anchored at three points and sewn into the waistband
• Heavy cotton pocket bags and lined rear pockets

Selvedge ID

• Sideseam, fly, and coin pocket selvedge ID

Leather Patch

• Heavyweight vegetable-tanned steerhide
• Dyed black finish
• Belt-through design
• Debossed Iron Heart graphic
• Please note: Continued washing (especially at higher temperatures) may cause shrinkage and deformities

Sanforized & One-Washed

• Sanforization is a post-weave mechanical process which removes most potential shrinkage from a fabric before garment construction
• To further reduce the risk of shrinkage, we wash the completed garment in an aggressive industrial washing machine. This process removes virtually all potential shrinkage.
• No further shrinkage is expected when washed according to our care guidelines

Stretch Details

• The waist will stretch out approximately 1" with wear. All other dimensions that are put under pressure will stretch proportionally to the waist

Care Guidelines

• We recommend washing this garment at 30°C with a low (or no) spin cycle. Hang dry, do not tumble dry

Measurement in inches

FAQs

Is this authentic Iron Heart?
Yes. All products sold by Rugged Gentlemen Shoppe are 100% authentic Iron Heart items sourced from Iron Heart Japan.

Why is this sold out elsewhere?
Iron Heart produces limited quantities and popular sizes sell out quickly on the official site and major retailers.

How fast do you ship?
Orders ship from our shop within 24–48 hours (business days).

Can you help with sizing?
Yes, contact us before ordering and we’ll provide real measurements for the exact pair in stock.