You’re meant to “raise” this kettle, not just use it. Nambu Tekki owners intentionally build up a mineral coating inside (called yuaka) by boiling hard or mineral water in the early days, which is what eventually makes the water taste so mellow. One reviewer said she was surprised how smooth and mellow the water tasted even though she doesn’t consider herself sensitive to flavor, and plans to keep caring for the kettle and use it for the rest of her life. Another bought hard mineral water specifically to speed up building that coating, treating it less like a kitchen tool and more like something you slowly develop a relationship with.
It reads as genuinely well-made to people outside Japan too. One reviewer from India called it elegant and said it was worth the price, praising the craftsmanship outright. Another buyer uses it every day specifically as a small dietary iron source, boiling her drinking water in it daily after reading that cast iron cookware can help with iron levels. That mix of real function and quiet daily ritual is what keeps people using it long after the novelty wears off.
The real usable capacity is smaller than the 1L label suggests. One reviewer measured it out and found that in practice, only about 800ml can be boiled comfortably at once. If you fill it closer to the full 1L, it tends to bubble out of the spout once it starts boiling, so it’s worth leaving the lid off when boiling a fuller batch and keeping expectations around 800ml per round for a clean pour.
A couple of small habits make daily use easier. The handle gets hot during boiling, so keep a pot holder nearby, and since the kettle itself has real weight to it, it helps to have your teapot or receiving vessel set at a comfortable pouring height rather than reaching down. The included instructions also walk through the seasoning process step by step, starting with hard water, so first-time cast iron kettle owners aren’t left guessing.