China’s authoritarianism has many faces, but rarely does it appear in the friendly, grandmotherly guise it has taken over the past week, as thousands of older women have shown up on the streets of the capital, their vigilant eyes eager to ferret out the smallest signs of trouble.

These graying, smiling, energetic women are the most visible sign of the 1.4 million volunteers enlisted to squelch protests, crimes and anything else that could embarrass the ruling Communist Party during its sensitive once-a-decade transition of leadership.

Security preparations began months ago for the party congress. Peaceful changes in China’s party leadership are rare; a successful transition would mark only the second one in the country’s history without blood or crisis.

As a result, Beijing has in recent days felt like a city under martial law. Authorities have commandeered virtually every block of downtown. Soldiers stand at rigid attention every few feet around the Forbidden City. Police cars idle on sidewalks and in alleys like cougars waiting to pounce. Guards march through Tiananmen Square carrying fire extinguishers, seeking to prevent Tibetan monks from lighting themselves on fire to protest Beijing’s rule in the region.

But the security blanketing the city is not all iron-fist tactics. A velvet glove of sorts — a gentler, subtler assertion of authoritarian power — has been equally ubiquitous.

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You see it in taxicabs, whose drivers were told to take off passenger window handles and lock their doors while passing through downtown to prevent any dissidents who might have made it past authorities at Beijing’s airports and train stations from tossing fliers — or Ping-Pong balls printed with messages, as one rumor suggested might happen.

You see the velvet glove online, where, a few days into the party congress, all Gmail and other Google-related apps suddenly went dead across the country. Normal methods used by some to get around China’s block on sites such as Facebook and Twitter also stopped working.

Kitchen knives have disappeared from supermarket shelves. A pigeon race for hobbyists scheduled for November was postponed with no explanation, presumably to shut down another avenue for anti-government messages. As authorities in some provinces have freely admitted, informants are being spread out among villages for the greater good of “helping to resolve conflicts.”

But the embodiment of the velvet-glove approach is the collection of older women who turned up last week eager to be sworn in as “Capital Public Security Volunteers.” In all, about 1.4 million security volunteers are at work in Beijing during the party congress, according to state-run media.

“Our duty is to guard our homes and streets and create a deterrent,” explained Zhang Liling, a 68-year-old woman with deep dimples, as she stood with a handful of other women to watch their street corner on the eastern side of Beijing.

After a morning spent with Zhang and others, it is hard not to acknowledge a particular ingenuity to the idea of harnessing the inherent nosiness among some members of this demographic.

Retired with time to spare, the women come to the job with an already highly developed penchant for gossip and zero hesitation about posing prying questions. Throw in free windbreakers and red arm bands that indicate their special status, and you’ve got an instant army of eyes and ears.

“I feel it’s my duty to take on this mission,” said a proud Bao Mianfeng, 62, a former teacher and party member. “No one forced me or any of us into this. It’s something we are happy to do.”

A successful party congress, Bao explained, means “a stronger and more prosperous country.” A stronger country means “one step closer to a well-off society.”

There is something fierce in how she says this, so full of conviction. But it is disorienting, too, hearing her warmth and sweetness in discussing the vital mission of blanket security.

But it is just another oddity in a week full of awkward juxtapositions — a week in which party leaders talk of democracy while clamping down on freedoms nationwide, in which reform is topic No. 1 while doubts about those same reforms are a close second, in which sweet grandmothers walk down the street with warm smiles on their faces representing a security apparatus that is anything but.

Liu Liu contributed to this report.