Grid two is two houses and their best-known blues. Dylan Blue from Versace launched in 2016, created by Alberto Morillas, with Calabrian bergamot, water notes, grapefruit and fig leaf on top, and black pepper, patchouli and violet leaf in the heart. Bleu de Chanel debuted in 2010 as an eau de toilette, Chanel's first new men's masterbrand since Egoiste in 1990. The eau de toilette here has a citrus accord with labdanum and sandalwood cedar, and the Parfum is the most intense of the line, with cedar and sandalwood from New Caledonia. Versace Man Eau Fraiche is the odd one out, a softer, fresher take on the original with white lemon, rosewood and sycamore wood. If you are comparing, spray Dylan Blue on one wrist and Bleu de Chanel on the other and wait twenty minutes. One is aquatic and spicy, the other is woody and dry.

Grid three is the wider men's shelf. Jimmy Choo Man Aqua is a woody-marine fougere with grapefruit, clary sage and salty moss, from the house that launched its first men's fragrance, Jimmy Choo Man, in 2014. Versace Eros arrived in 2012, made by Aurelien Guichard, with mint, green apple and lemon over tonka, ambroxan and Madagascar vanilla. Dior Homme Cologne was redone in 2013 by Francois Demachy around Calabrian bergamot, grapefruit blossom and musk, and it is the cleanest thing here. Armani Beauty's Stronger With You Intensely goes the other way, with pink pepper, lavender and vanilla in an amber woody fougere. What I would skip is spraying the warm, sweet ones, Eros and Stronger With You Intensely, on a hot afternoon. They get heavy quickly, and the cologne and the Aqua are made for that kind of weather.

Buying a cologne for yourself is easier when you decide what you want it to do. If you want fresh and quiet, the Dior and the Coach are the simplest. If you want a bit of spice with the blue, Dylan Blue and Bleu de Chanel are the classics. If you want something people will comment on, Eros and the Armani will do it. Whichever you choose, wear it for a full day before you decide, and spray it on skin, not on your shirt.

Once you know what Coach Blue does on your skin, the useful next step is smelling it against its neighbors, because blue fragrance is a crowded family and the differences are small until you test them side by side. For the fresher end, I would start with Bleu de Chanel in the eau de parfum, the Versace Man Eau Fraîche Extrême and the Light Blue Pour Homme from Dolce & Gabbana. For something deeper to wear after dark, try Dior Homme Intense, BVLGARI Man in Black and the Gucci Guilty Intense. The Acqua di Giò Elixir from Emporio Armani sits somewhere in the middle, and the Coach Gold and Cherry parfums keep things in the family if you like the bottle. What I would skip: the Spicebomb Night Vision for an office, the name tells you it is meant for evenings out. If you want to keep browsing, I also put together Versace Cologne and Coach Cherry Perfume.