Iwachu Japanese Iron Cast Teapot Tetsubin Gold and Cinnabar Goldfish

Tetsubin: A Japanese Waterkettle (or iron teapots) evolved from larger teapots used centuries ago. These where used to heat the water for tea and thus providing warmth to the household during the winter.
The goldfish used in this original Iwachu design stands for good fortune and luck. Iwachu is one of the finest manufacturers of Japanese iron teapots. The company is over a 100 years old and holds tradition high. Today, craftsmen at Iwachu pay respect to this tradition by infusing each product with skilled precision and detail throughout the entire manufacturing process. The superior quality, beauty, and lasting durability of Iwachu tea pots and cups have earned them the worldwide reputation as the leading manufacturer of authentic Japanese tetsubin.

Tetsubin the Japanese name for iron cast pots are often decorated with reliefs and designs on the outside. They range widely in size, and many have unusual shapes, like bells or are in an angular shape, making them popular with collectors. Some Tetsubin teapots are easily sold for a $2500.
The designs may differ, from abstract patterns to symbols or drawings. You find them as well in many different colors, depending on the Japanese tea sets.

The advantage of an iron teapot is that Cast iron teapots evenly distribute the heat throughout the pot for a more even temperature, which does a better job of extracting the flavors and health benefits from the tea leaves.
The best is to use pure water, we've got a spa close, so I take my water straight from the mountains, but if that's not possible, go for the nearest thing possible. It makes a difference in the flavor of the tea.

This review is from: Iwachu Japanese Iron Teapot Tetsubin Silver and Black Goldfish (Kitchen).

The price and quality of this teapot may mean its greatest appeal is to collectors and folks who like decorative things. I'm not a teapot collector, but I've acquired a few just from trying to find one that works best for me. Although a long time tea drinker, I only recently got interested in cast iron after a visit to a local Thai restaurant where we were served tea in a cast iron pot. It seemed the pot kept the tea hotter for far longer than my ceramic ones at home, and I found the heavier weight easier to handle, if that makes any sense.

After receiving this teapot I tested it along with a quality ceramic pot of similar size and shape, to see if my previous impression held true. The ceramic pot kept the water just as warm as this teapot. I tested them twice, once with cups poured out at half hour intervals and once after the teapots were filled with boiling water and left to sit on the counter top for an hour and a half. I didn't use a thermometer, but if the cast iron pot kept the water hotter, then the difference was negligible. I should note that another ceramic pot I tested did not keep the water quite as warm as this pot or the other one. Realistically, unless you don't mind lukewarm tea, you'll want to empty the pot well before an hour or so is up. It's a small sample size, but cast iron teapots probably do not keep tea hotter for longer periods than ceramic ones.

This is just one of the reviews made at Amazon, this one is written by Mike R. -
Here you can read the other tetsubin teapot reviews

Traditionally Japanese iron teapots, known as Tetsubin, where used to boil water as well as to brew tea. But the Old Dutch Nobility cast iron teapot is just ment for brewing, not for boiling on the stove. Old Dutch teapots uses a black enamel coating inside the teapot to prevent rusting. Unlike ceramic teapots, the cast iron teapots retains the heat for a long time and won't chip.
After you've used the Tetsubin teapot the best thing to do is to rinse it and dry before storing.

G&H Tea Services Otani Japanese Tetsubin 25-Ounce Teapot and Trivet, Red

G&H Tea Services Otani Japanese Tetsubin 25-Ounce Teapot and Trivet, Blue

G&H Tea Services Otani Japanese Tetsubin 25-Ounce Teapot and Trivet, Green

G&H Tea Services Otani Japanese Tetsubin 25-Ounce Teapot and Trivet, Natural