Ms. Fan has been buying Japanese makeup for about five years and was turned on to it by a trip to a counter of Shu Uemura, a Japanese brand that has been sold in the United States since 1997, but now is available only online at shuuemura-usa.com. “There were so many colors and textures that I became addicted,” she said. Another Japanese brand, Shiseido, is also widely available here (last year the company acquired the popular mineral-based line Bare Escentuals), but Ms. Fan was interested in more elusive quarry. She started researching Japanese brands that were available only in Asia and ordering them online. Koji eyelash curlers, Jill Stuart eyeshadow palettes and Kiss Me Heroine Make Smooth Liquid Eyeliner (“super thin,” she said) are some of her favorites.

“I love how the brands focus on perfection,” she said, “perfect skin, perfect lips, perfect lashes. There’s such meticulous attention to things like how a mascara brush works or how black a new eyeliner is.”

Many of the Western women hunting for Japanese makeup use Adambeauty.com, a Hong Kong-based site that they say offers the best prices, but sasa.com, ichibankao.com, mihokoshop.com and imomoko.com are also popular. Quite a few also scour the offerings from the eBay seller AlphaBeautyUK. Some send friends who live in or are visiting Asia a shopping list. Gloria Yang, 25, a laboratory technician at Sephora who lives in Los Angeles, had her sister interrupt a vacation in Taiwan to go to Watsons, a drugstore. Ms. Yang wanted to stockpile mascara, both Kiss Me Goodlash Power Beam Eyes, which is smudge- and water-proof, and Fairy Drops, which has an undulating wand. “My sister told me they didn’t have them in the store,” she said, “so the sales associate actually ran over on foot to grab them from another one.”

The sisters’ father lives in Taiwan, but Ms. Yang said she hasn’t asked him to get her anything because “he thinks I spend too much money on makeup already,” she said.

Ms. Yang’s favorite thing about the products is not that they could give her an alabaster face and intensely lined eyes, a look she called “creepy,” but that, she said, they’re incredibly water-resistant — built to withstand the many humid climates in Asia. “Everything else smears on me,” she said.