As temperatures dip in Japan, women are covering up in knitwear while men are increasingly fond of flashing their expensive underwear.

A new penchant for women's knits - and knitted dresses in particular - is being combined with an array of accessories: bags, caps, mufflers, legwarmers, and necklaces with knitted bobbles.

Many of the knit dresses in the stores this winter are priced at around JPY10,000 (US$84.62) to JPY20,000 and there is a very wide variety from body-hugging types favoured by the young to classier loose-fitting dresses.

Textural variety abounds as well, with choices ranging from smooth, fine-gauge knits to chunky cable patterns.

Japan's men, meanwhile, are spending more on underwear as a fad for low-on-the-hip jeans means more men will be showing the tops of their underwear in public.

"Sales of men's underwear have been rising monthly," Ken Ueno, the undergarment buyer at up market Isetan Department Store in Shinjuku, told the weekly Asahi magazine.

"We have about 12,000 visitors a month. Although overall customer numbers are up, this section in particular is a top-selling sales place. We've sold over 30,000 items here."

The average price of luxury shorts is about JPY5,000.

The boom for men's' upmarket underwear has also sparked the creation of 'Tre Punti,' Japan's first male underwear catalogue.

By Michael Fitzpatrick.