“I am having to bring it back to our heritage,” Ms. Sander said, referring to her start-up business in 1968, when she was 25, that became a publicly listed company 21 years later.

In the late 1990s, after a tempestuous series of win/lose deals in her relationship with Prada, the company’s owner at the time, Ms. Sander, who designed sleek chic for modern women, twice left the house, and walked out for good in 2004.

The collection on Saturday is men’s wear. It will be shown in the Piazza Castello showroom, the site of her previous shows. Ms. Sander, 68 , is eager to make up for lost time and to include what she has learned in the missing years.

Working with Uniqlo, part of the Fast Retailing Co. of Tokyo, from 2009 to 2011, Ms. Sander created a +J line of streamlined style to her exacting standards — without a lot of zeros on the price tags.

“After the experience in Tokyo, this is another experience,” the designer said, explaining how exciting it had been for her “to work on a project in a completely new world, to get an idea and to cultivate a classy product.”

“It was great for me. I learned a lot,” she added.

Having spent some of those wilderness years traveling for pleasure from the Hamburg home she shares with her partner, Dickie Mommsen, Ms. Sander is ready to focus on dressing the ever-traveling folk of the global universe, including the 40 million people daily who use the commuter rails in Tokyo.

“I was quite far away and I was in a new project — and then when I came back, I saw the position of luxury brands,” Ms. Sander said, referring to the fact that LVMH and Gucci were “all related to accessories.”

The irony in that is that her final bust-up with Patrizio Bertelli, the chief executive of Prada, was over expanding her lines of bags and shoes. But all that is now behind her as she plans her new collections.

“You need a clean, modern approach and to have quality: clothes that are three-dimensional and not classic and boring,” she said. “It is a very thin edge.”

The world has changed deeply and irreversibly since the days when the Jil Sander label represented a sheltered sisterhood of intelligent women looking for clothes to match a liberated spirit.

There was no Twitter to dismiss a comeback in 140 pithy characters; there were no bloggers eager to express the fashion views of the dot-com generation; and no virtual stores to compete with those bricks-and-mortar spaces created for Jil Sander by the architect Michael Gabellini.

For Ms. Sander, who describes cleaning and tidying the Uniqlo stores with her own hands, terrestrial stores are a necessity. She said those store concepts were “timeless” and would be built up again by Onward Kashiyama, now the owner of Jil Sander.

But however pure and perfect the retail spaces, there is going to be an elephant in the room. Maybe two. The first is Raf Simons, the Belgian designer who is her successor at the Jil Sander label. Although Mr. Simons has since been tapped as the creative director at Christian Dior in Paris, there is still a lingering feeling that he was pushed out ungraciously by Ms. Sander’s comeback.

Then there is Phoebe Philo, the 30-something designer at Céline, who has created a female following similar to those women who were wedded to Jil Sander’s original style and her serene, no-fuss attitude. Ms. Philo, who has made minimalism her mantra, stood out against the girly glamour of the new millennium. Céline has even offered women streamlined pants — the workhorse of a working mother’s wardrobe and an update of the Jil Sander legacy.

Ms. Sander said that “fashion has always had ups and downs,” referring to the way that women who had seemed “intelligent and emancipated” turned to girly glamour.

So how does Sander now view her meticulous simplicity?

“I’m working less on decoration, more on form — pattern-making and materials, with a lot of dresses in the collection — in a good modern way,” she said, explaining that she had already prepared the bulk of her 2013 women’s collection.

She talked about a double-breasted jacket and fresh fabrics for her iconic blazers, explaining that “when I go out at night, I don’t want to change and become a completely different woman.”

Ms. Sander also said that she did not want clothes to make a woman feel like a “senior” or a “madame.” But, at the age of 68, she is a senior, just a little younger than Coco Chanel when she made her postwar comeback in 1954.

Is Ms. Sander going to follow Karl Lagerfeld, her fellow German-born designer, into her 70s and beyond?

“My family asks, ‘What are you thinking?’ But if you have been working creatively, you are easily seduced to come back,” Ms. Sander said. “No one can say: ‘I work until I die.’ I am still quite energetic. But you can’t think 10 years ahead.

“You have to have love and passion,” she continued. “The beauty is that I can be back in a company I know. I will do my best.”