21oz Selvedge Denim Straight Cut Jeans IH-634S-B - Indigo Overdyed Black

The Iron Heart IH-634S-B in 21oz indigo overdyed black Japanese selvedge denim is available at Rugged Gentlemen Shoppe with fast local shipping and easy returns. Iron Heart produces limited runs of each model, and popular sizes are often difficult to find. If your size is available, you can secure it here while stock lasts.

Our traditional straight cut, medium rise jeans, made from 21oz overdyed indigo selvedge denim. To create this darkened variation, we take a pair of standard IH-634S jeans and steep the entire garment in black dye using a direct dyeing process. This stains the indigo denim and stitching, with the added bonus of removing all shrinkage from the fabric. A unique middle ground between our traditional indigo and black denims, over time the fabric will gradually fade with blue-tinged hues in high-wear areas.

Please note that previous versions of these jeans were overdyed using sulphur dye. Due to the environmental impact of sulphur dyes, we have decided to switch to a direct dyeing process when overdyeing our heavyweight denims. The only noticeable difference is that this new process does not oxidise the brass hardware as previously. You can still expect these jeans to age and fade similarly to older models.

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 Denim - Overdyed Black

• 100% cotton
• Woven with a double twisted weft yarn
• Indigo rope-dyed warp / white weft
• Right-hand twill weave
• Post-construction, this garment is overdyed using black direct dye
• This denim will fade with indigo-tinged hues through wear and washing

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
• Natural finish
• Belt-through design
• Debossed Iron Heart graphic
• Please note: Continued washing (especially at higher temperatures) may cause shrinkage and deformities

Sanforized, One-Washed & Overdyed

• 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.
• Following this, a high-temperature overdyeing process removes any remaining potential shrinkage
• This garment may fit slightly smaller than its non-overdyed counterpart. Please refer to our measurement charts carefully
• No further shrinkage is expected if washed in accordance with our 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.