If you are the kind of person who wears mostly black, and if you have ever tried to add pieces to your wardrobe by rummaging through the colour-sorted racks of a vintage store, then you have probably at one point or another felt like you might never find hidden fashion treasures. In fancier boutiques, where the lighting is designed by a professional and each item is lovingly displayed on its own plush hanger, black clothes look regal, sturdy, distinctive — like pieces of the architecture that you can take home. But in a resale store (or even a big-box store, where everything has been smushed together on overstuffed shelves by a bored salesgirl who can’t wait for her next Snapchat break), the inky sea of black clothing is a nightmare. Every item on the rack looks the same, so it's nearly impossible to hone in on any one piece that works. The only way out is by picking through. You must deep-dive into a pile of onyx if you want to return from the depths with something great. And that effort is why all of my most prized pieces tend to come in black: I had to dig for them, through rubble, with my bare hands.One such deep dive into the secondhand abyss changed my life — I know, I know, the term “changed my life” when applied to clothes is something that is usually tossed off in blasé quotes by actresses talking about how liberating it was to finally wear boyfriend jeans. But in this case, I fully mean this: This one item of clothing changed my life.Here’s the story: Three years ago, knee-deep in witchy garments in a Beacon’s Closet in Brooklyn, I felt a black, wisp-thin Jil Sander polo neck so delicate and soft that I almost missed it. It was made of the kind of springy lycra-spandex that shrinks up so small that it is difficult to imagine it fitting one’s arm, let alone the entire torso of a grown woman. I laughed when I first saw it, thinking it was perhaps one of those chic baby pieces that Alexander Wang designed for his toddler niece . But checking the size (and then googling it — European size 40, what the hell are you in English?), I saw that it was somehow supposed to stretch to accommodate my body. I felt like it offered me a challenge I could not refuse. So it came with me to the dressing room.Every time I look at this absurdly tiny polo neck, I still don’t know how they (either Jil Sander or Raf Simons — I don't know who was responsible) did it — how this flimsy piece of black material can make me feel more glamourous than anything I’ve ever owned. Because it fits like someone poured it onto my body. It fits like I had it made. It fits like I always dreamed a polo neck would fit: no gapping, no bunching, nothing but a seamless casing of sleek fabric that hugs every inch of my top half. It holds all the curves, and then smooths them out. It makes me feel almost bionic.During the cold months, I wear the polo neck almost every day (unless it is at the dry cleaners, when I actively miss it like a long-lost child and think about all the adventures we will have together when it gets back). When it got chilly enough last week for me to pull it out again from its sacred space in my wardrobe, I welcomed it back into my life with a yawp of glee, like one of those dogs on YouTube welcoming home a soldier with ecstatic, sloppy kisses.This polo neck is my north star, the end of my quest, my excalibur. True, I got it at an insane discount (£800 for the original, and I paid £40. Shop consignment forever, I guess?), but its continuing power over me is more than just the afterglow of an epic steal. Finding the Jil Sander piece was the crowning moment of a decade-long hunt for the perfect black polo neck, a hunt that has led me across the globe and through at least 20 different contenders before I found the one. I have been obsessed with them ever since I started wearing them in college. I did this the way most students studying art history who want to be taken seriously in seminars do: awkwardly, with a faint air of desperation — until I realised that what started out as a costume was feeling more and more like an expression of my best self. I found that when I wore a black polo neck, I always felt more powerful, more seductive, more clever.In my experience, a black polo neck is simply the best thing a girl can wear when the weather turns. Polo neck sceptics, hear me out on this.Black polo necks are often derided as cliché, as the chosen uniform of the try-hard. This reputation dates back to the late 1950s and early '60s, when the beats took what was historically a sporting and military undergarment and turned it into a cultural signifier of urbane sophistication, topped off with a fey little beret and a dangling cigarette. Around the same time, the poets and jazz flautists and their hangers-on began to wear polo necks en masse, and the press began to criticize the “bohemian” underground scene, mocking a subculture that prided itself on affected intellectual superiority.