Some weeks a young woman comes in with a photograph torn from a magazine. Louise Brooks, 1929. The same black line at the jaw, the same hard parting, the same shadow at the nape. She wants that cut, give or take a Glasgow autumn. The photograph she is holding has been asked for, in one form or another, for as long as her great-grandmother has been alive. A hundred years on, the bob still does what almost no other cut manages. It changes the room it enters. What follows is the history of the bob haircut, told from the chair.

Before the 1920s, there was a Polish hairdresser in Paris

Most accounts place the bob in the flapper era. The lineage starts a decade earlier. In 1909, a Polish hairdresser called Antoni Cierplikowski, working in Paris under the stage name Antoine de Paris, began cutting women's hair to the chin. He told reporters the idea came from accounts of Joan of Arc, the fifteenth-century French heroine, cropped close, fighting in armour.

Antoine was born in Sieradz in 1884. He moved to Paris in 1901, having apprenticed under his uncle in Łódź. The salon he set up in Paris would make a hairdresser, for the first time, a name above the door. His clientele eventually included Coco Chanel, Greta Garbo, Eleanor Roosevelt, Sarah Bernhardt, Queen Marie of Romania. He was cutting bobs more than a decade before the rest of the world caught up.

That detail matters. The bob was not invented by the women who wore it in their thousands in 1924. It was invented for them, quietly, by a man who took Joan of Arc literally and brought the cut down from the fifteenth century to the salons of Paris.

The Castle bob, and a woman about to have her appendix out

The next chapter of the bob is American, and accidental. Irene Castle, half of the most famous ballroom duo of the 1910s, cut her hair short in 1914 or 1915, depending on which account you read, before going into surgery for appendicitis. She wanted something easier to wash while she was recovering. She was not trying to start anything.

When she came back to the dance floor, she wore a turban. Friends pressed her to take it off. The next public dinner she went to, she went without it, holding the line in place with a pearl-stranded headband. The hairstyle was christened the Castle bob, and within a year it had a name, a wearer, and a young American audience already half-prepared to ask for it.

Most accounts also nod to Clara Tice, an artist in New York's Greenwich Village, as the first public American to wear the cut, ahead of Castle's larger broadcast. The provenance is contested in the way these things tend to be. Many hands, one moment.

The decade the bob became the woman

By 1920, the United States had about five thousand hairdressing salons. By 1924, the Smithsonian records, twenty-one thousand. The bob was a small economic revolution as well as a cultural one. An entire trade had to learn a new pair of scissors. Some refused. Hairdressers turned women away. Barbers picked up the work the salons would not take.

Preachers were against it. The Washington Post published a piece in 1925 called Economic Effects of Bobbing. There is an American line from the period, still quoted, that a bobbed woman is a disgraced woman. There were divorces over it. F. Scott Fitzgerald published Bernice Bobs Her Hair on the first of May, 1920, and the story dramatised what was already happening in the country. A young woman ostracised in her own circle, for the sake of a few inches at the jaw.

The cut, of course, was not only hair. It was less corsetry. It was the dance floor without a chaperone. It was the cigarette, the car, the vote (in the United States in 1920, in Britain on the same terms as men in 1928). Hair shortened in step with all of it. By the middle of the 1920s, the bob was the dominant female hairstyle in the western world, and the variant cuts had begun to multiply.

The look came in degrees. The Castle bob ended just below the ear. The shingle was tapered close at the nape, the way a man's hair was cut. The Eton crop, named after the boys' school's collars, went shorter still and was sometimes worn with a centre parting and a flat marcel wave at the temple. Each was a slightly different argument about what the cut should mean. The Eton crop is the line that runs forward, in time, into a history of the pixie cut, which has its own century behind it.

Louise Brooks, and what the screen taught the mirror

The image most people carry, when they say the word bob, is Louise Brooks in 1929. Pandora's Box was filmed in 1928 under the German director G. W. Pabst, and released the following year. Brooks plays Lulu. The cut is short, sleek, parted high, black as wet ink, ending at the jaw with the cleanest possible line.

That is the photograph our winter client brought into the consultation room. It is the photograph nearly every modern bob revival reaches for. The British Film Institute, looking back, called the Lulu bob cinema's most imitated haircut, and they were not wrong. Uma Thurman in Pulp Fiction, Audrey Tautou in Amélie, half the magazine covers of the last fifty years. The same line at the jaw, traced from one frame of a 1929 silent film.

Brooks's hair worked because the cut held a sheet of dense, dark hair to a perfect parallel line. For the modern equivalent in our city, particularly under a bob worn long at the front, we cover the technique in balayage on dark hair, which is the canopy work most short cuts need.

What endures, when a cut endures

Standing at the chair for our twenty-eight years, what we notice is what the bob does to the architecture of the face. The line at the jaw lifts the line at the cheekbone. The line at the cheekbone lifts the line at the eye. A well-cut bob is a piece of structural work. That is why it has lasted.

The chair you only leave when the work is right.

The brand line applies to no cut more than this one. A bob asks for precise tension, dry-cut adjustments, a parting that sits down without coaxing, a nape taken to the millimetre rather than the half-inch. There is nowhere to hide. The line is the line.

Vidal Sassoon, 1964, and the bob without the rollers

The bob was revived in London, in 1964, by an East End hairdresser called Vidal Sassoon. He had opened his first salon in London in 1954. By the early 1960s he was cutting in a new register. Geometric. Angular. On a horizontal plane. No rollers. No lacquer. The British press called it the Sassoon bob.

The five-point cut, the most famous of the era, was created in 1964. It was first cut on British Vogue's Clare Rendlesham, then on the model Grace Coddington, who was photographed for the magazine wearing it. Mary Quant, the designer whose miniskirt was already doing its political work, wore the geometric cut at her own runway shows. The 1964 photograph of Quant and Sassoon together is one of the defining images of mid-century British style.

What Sassoon had done, by his own description, was take the bob off its high-maintenance rollers and lacquer and let the cut hold the shape on its own. The architecture was inside the hair, not on top of it. This is the lineage every modern bob inherits. A cut that should fall correctly without anyone doing anything to it later.

By the next year, Queen and Elle had run the cut in their pages. It reached New York. By the end of the decade the bob had gone through Nancy Kwan, photographed by Vogue with a heavy chin-length cut of her own, and through Peggy Moffitt, whose asymmetrical bowl became the most photographed five-point variant. The London chair had restarted a London cut. The lineage went back to Antoine in Paris, and forward to nearly every salon working today.

What we ask for, when a client asks for a bob

A century from Antoine, sixty years from Sassoon, the bob arrives at our consultation table in two main forms. The first is the heritage line. The Brooks, the Castle, the precise high parting and the clean jaw. The second is the lived-in bob, softer, longer at the front, shadowed at the root, often with the kind of hand-painted lift that comes through balayage rather than foils.

Either way, the work begins with the consultation. We look at the line of the jaw. We look at the way the hair falls when wet, and how it falls again when it is dry. We look at the cowlick at the crown, the weight at the nape, the density at the canopy. The bob is not generous to a cut that misreads any of these. A millimetre matters at the jaw in a way it does not on a longer cut. Get it wrong and the cut sits wrong every morning until it grows out.

The hair tells us, when it is wet, what it is going to do when it is dry. We work with the natural fall, not against it. A bob cut in resistance to the way the hair wants to lie is a bob that fights its owner every morning. The cut should agree with the head it sits on.

For the colour worn under a modern bob in our city, we go into more detail in hand-painted balayage in Glasgow. The hand-painting is what gives the canopy of a short cut its movement, particularly on a dark base.

For the wider lineage, the pillar piece on the cuts that shaped each era sits the bob alongside the gibson, the shag, the pixie and the rachel.

The craft view of what came before all of these cuts is in a colourist's history of hairdressing, the long thread from the bowl to the chair.

The clean line, a hundred years on

The lesson the bob teaches a colourist, after twenty-eight years of working under one form of it or another, is that a cut endures because it is honest. The bob shows everything. It shows a heavy nape, a thin canopy, a low ear, a tight cowlick. It shows good condition and it shows poor condition. It does not flatter what is not there.

That honesty is what has kept it on women's heads for a century and counting. Antoine cut it in 1909 because the Joan of Arc accounts had given him a picture to copy. Castle cut it in 1915 because she had a surgery to recover from. Brooks wore it in 1929 because Pabst put a camera on her. Sassoon cut it in 1964 because the rollers had to go. The reasons keep changing. The line at the jaw does not.

When the next young woman comes in this spring with a photograph in her hand, Brooks or Quant or something more recent, we will look at the jaw, the parting, the canopy and the nape, and we will tell her what we tell every bob client. The cut is a discipline. The chair, on Paisley Road West, is by appointment.