'Yutanpo'

A non-electric heat source.

'Aa, yutanpo saikou.'
"Ohhh, yutanpo rules!"
Ashinano, Hitoshi. 2005. Yokohama Kaidashi Kikou. Chapter 127. Vol. 13, Page 106, Panel 2.

'Yutanpo' is the Japanese word for "hot water bottle". It is also spelled 'yutampo'.

Typical Yutanpo

If you talk about 'yutanpo', this kind would be the one that comes to the mind of most Japanese people. It is made of zinc-coated steel.

I haven't looked but I'll bet Alpha's yutanpo looks like this one.

Yutanpo should be used with a cover or wrapped in a towel. Be careful not to burn yourself.

Modern Yutanpo

Plastic-made yutanpo are safer than steel ones and getting more common these days.

Antique Yutanpo

This one is a museum piece that is made of ceramic. It was used decades ago. This one is part of the collection of Arakawa Museum of Aqua.

Conclusion

Probably Alpha has only one yutanpo and that's why they share blankets.

If you are using a rubber-made hot water bottle, that is good. It must be safer than steel-made yutanpo.

Links

What Is This? by Nonaka Kunihiko and Kawakami Mamoru

You can find out more about yutanpo.

Appendix: Shoga-yu

Shogayu is a drink made from ginger, sugar and starch. It tastes spicy and sweet. It is served hot. It is said that it makes you feel warm.

You don't usually put brandy in shogayu.

Above picture shows Udon-ya's instant shogayu.

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