Frequently Asked Questions

Each NAMBUTEKKI kettle is hand-poured by master artisans in Morioka using traditional sand mold casting (sunamono) — a living craft passed down through generations since the Edo period. Unlike mass-produced kettles made in factories using industrial molds that produce thousands of identical pieces per day, our artisans create one kettle at a time. Each piece bears subtle variations that make it uniquely yours — the hallmark of true handmade craft.→ Read the full story in our Journal

Authentic Nambu ironware has several telltale signs: a visible artisan signature (mei) on the bottom, the characteristic texture of sand-cast iron (not smooth like factory castings), precise fitting between body and lid, and proper weight distribution. Every NAMBUTEKKI kettle comes with a certificate of authenticity signed by the master artisan who created it, along with details of our Morioka workshop.→ Discover the 400-year legacy behind each piece

Yes — scientific studies have confirmed that water boiled in uncoated cast iron releases trace amounts of ferrous iron (Fe²⁺) into the water. This form of iron is highly bioavailable, meaning your body absorbs it easily. A typical cup of tetsubin-boiled water contains approximately 0.1–0.3mg of iron, contributing gently to daily nutritional intake. Beyond iron, many tea enthusiasts report that tetsubin water produces a softer, sweeter taste compared to other boiling methods.→ Explore the science behind iron-enriched water

Absolutely. All NAMBUTEKKI iron kettles are fully compatible with induction cooktops, as well as gas, electric ceramic, halogen, and even open flame (with proper trivet). Cast iron's ferromagnetic properties make it ideal for induction heating. For best results and longest kettle life, we recommend using medium heat settings and avoiding rapid temperature changes.

With proper care, a NAMBUTEKKI kettle is designed to last generations. In Japan, it's common for families to pass their tetsubin down as heirlooms — some pieces in use today are over 100 years old. The iron actually improves with age, developing a rich internal patina that enhances both performance and appearance. We back every kettle with our lifetime craftsmanship guarantee against manufacturing defects.

Before first use, follow these steps: (1) Rinse the interior with warm water — no soap needed. (2) Fill to 70% capacity and bring to boil. (3) Pour out the water and repeat this process 3-4 times. (4) On the final boil, reduce to simmer for 10 minutes. This process washes away any manufacturing residue and begins forming the protective mineral layer. After each subsequent use, always empty remaining water and dry thoroughly with a clean cloth, leaving the lid off until completely dry.→ Read our complete tetsubin care guide

Light surface rust is normal and easily remedied. Simply scrub the affected area gently with a soft brush or cloth, then boil water as usual. The mineral patina will naturally restore itself through regular use. To prevent rust: always empty water after use, dry thoroughly, store with the lid off in a well-ventilated area, and use the kettle regularly. Rust from neglect is more serious — if you notice deep pitting, contact us for professional restoration guidance.→ Detailed rust prevention in our care guide

We strongly recommend against leaving water sitting in your tetsubin for extended periods. Stagnant water can accelerate rust formation and may develop an off-taste. After each use, pour out any remaining water and allow the kettle to air dry completely. If you need to keep hot water for serving, transfer it to a porcelain or glass vessel instead. Your kettle will thank you with decades of faithful service.

The exterior requires minimal care. Simply wipe with a soft, dry cloth after use to remove any moisture or fingerprints. For the beautiful textured patterns (arare, floral, etc.), avoid abrasive sponges or harsh chemicals. Never put your kettle in a dishwasher or submerge it fully in water. Over time, the exterior will develop its own characterful patina — embrace it as part of your kettle's unique story.

All orders ship directly from our workshop in Morioka, Iwate Prefecture, Japan. Standard international shipping takes 5–10 business days. Express shipping (3–5 business days) is available at checkout. Each kettle is individually wrapped in traditional washi paper and placed in custom-fitted wooden boxes before being securely packed for international transit. You'll receive tracking information via email within 24 hours of dispatch.

No catch — free standard international shipping on all orders over $150. For orders under $150, a flat rate of $15 applies to anywhere in the world. We believe you shouldn't pay extra to receive the craftsmanship you've invested in. Express shipping options are available at competitive rates for those who need their kettle sooner.

Import duties and taxes vary by destination country and are the buyer's responsibility. However, good news for US customers: under the US-Japan Trade Agreement, most cast iron cookware items enter duty-free. For EU customers, VAT is typically collected at import (we handle DAP delivery). We provide all necessary customs documentation with every shipment. Contact us if you'd like an estimate for your specific country.

Lifetime Craftsmanship Warranty: Every NAMBUTEKKI kettle is guaranteed against defects in materials and workmanship for life. If your kettle ever fails due to a manufacturing issue, we'll repair or replace it free of charge.

30-Day Return Policy: If you're not completely satisfied, return unused items in original packaging within 30 days for a full refund.

Damaged in Transit: Photograph the damage upon arrival and contact us within 7 days. We'll arrange a replacement immediately at no cost to you.