TOKYO -- Japan's brick-and-mortar clothing retailers are looking to digital sizing technology to keep up with online rivals as they push the limits of a custom fit.

At some of its Uniqlo stores, casual clothing group Fast Retailing is trying out a system that can take body measurements in an instant. Department store operator Isetan Mitsukoshi Holdings has its own system that scans customers' feet to create semi-customized shoes.

In Japan, online marketplace Zozo pioneered the use of data-capturing bodysuits to offer clothes with a better fit than off-the-rack products. Now stores are fighting back.

What these retailers are really after is data about their shoppers, which can help develop better sales plans and new products.

A Uniqlo outlet in Tokyo's Shinagawa Ward has a 3D measurement system. Customers stand in a booth where their measurements are taken instantly using 16 sensors. The system takes a photo of the customer that includes measurements, such as arm and leg length, and waist size. These are displayed on a monitor. Customers can store their data on a smartphone app and use it for later online or semi-customized orders.

Taking customer measurements precisely is a key part of Fast Retailing's drive to turn itself into a "digital consumer retail company."

Others are following Fast Retailing's lead. Danish shoemaker Ecco on Feb. 20 set up a pair of foot-measuring devices at the Isetan Men's annex of the Isetan store in Tokyo's Shinjuku district. The devices measure the length and width of the feet, as well as ankle shape. The data is used to design customized insoles, which are then fabricated using a 3D printer. The process takes about an hour.

Last September, Takashimaya, a department store chain based in Osaka, set up a 3D measuring device in the women's shoes department of its store in Tokyo's Nihombashi district. Sensors measure the shape of customers' feet in just 10 seconds. The system then recommends shoes that most closely fit the customer's data from among 288 options.

A Takashimaya employee recommends shoes to a customer using one of the department store's new sizing machines.

Apparel sales at Japanese department stores have been sluggish in recent years due to fierce competition from inexpensive fast fashion brands and online retailers. But they have one important edge: their skill in offering clothes with a good fit, thanks to their experience with tailor-made men's clothes. A Takashimaya representative said taking customers' measurements digitally gives salespeople more contact with potential buyers who might otherwise just browse, making a sale more likely.

If having customers' measurements on file boost orders for custom-made products, department stores can also cut costs by reducing stocks of unsold clothing.

Fast Retailing and department stores are trying to counter Zozo and the other online upstarts. In 2018, Zozo began distributing an upgraded version of its Zozosuit to coincide with the launch of its private-label products. The Zozosuit is a closefitting garment equipped with sensors that let customers take precise body measurements, which they can then use to order custom-fit clothing.

In the early days, buying off-the-rack clothes online was a hit-or-miss affair. The Zozosuit allowed customers to get a custom fit without visiting a store -- a unique business model.

But there have been challenges. Zozo has sent out more than 1 million of the high-tech suits, but, said CEO Yusaku Maezawa, "Fewer people took their measurements than we expected." The suit also proved less popular than Zozo hoped: It was difficult to put on and measurements were frequently inaccurate. Some customers complained that they ended up with the wrong size clothes.

Tadashi Yanai, president and chairman of Fast Retailing, believes it is much better to go to a store and have your measurements taken by a professional than to put on a fiddly sensor suit.

But despite the snags, the race is on among clothing sellers to develop technology to make 3D body measurements using smartphones. Last November, Original, the California-based operator of online dress shirt website Original Stitch, began offering a service that uses artificial intelligence to scan the whole body by analyzing smartphone photos.

If such tools can be perfected, it will no longer be necessary to visit a store to get custom-fit clothing. But for now, stores that accurately trace the many shapes and sizes of their customers will go a long way toward taking the guesswork out of fashion.