I might be biased because I'm really into Japanese designer brands. I admire their dedication to high-quality materials, superior craftsmanship, unique production process, and overall artistry.
Everything I love about Japanes fashion I found it in Shibuya (along with its neighbours Harajuku and Omotesando). From "Americana" influenced heritage brands like Visvim, Kapital, Blue Blue Japan...etc to high-end designer bands like Ambush, Comme Des Garcons, Bape...etc To Japanese streetwear like undercover, Mastermind, Undefeated, Neighbourhood..etc then you have other dope Japense brands doing their thing like Beams Plus, OrSlow, Needless, Wacko Maria, Engineered Garments, Journal Standards and dozens of independent concept stores..etc. And don't get me started on Japanese denim
like Studio D’Artisan, 45RPM, The Real McCoy, Oni, Momotaro...etc
in addition to that you have great non-japanese stores like Acne Studios, Saturday NYC, Noah, Maison Kitsune..etc around the area
all these brands and a lot more within walking distance from each other thats why, to me, Shibuya is greatest shopping city in the world.