It takes about 17 minutes to traverse Tokyo's consumer generation gap. In the city's youth mecca of Harajuku, goths, lolitas, rockers and young fashionistas fill a shopping landscape crowded with boutiques and brand-name franchises.
Nine stops away on the city's Yamanote loop line in Sugamo, the river of human traffic turns greyer and slower as it files past shops selling thermal underwear, hearing aids and orthopaedic socks. Shop entrances have been modified to accommodate wheelchairs, and hand-written signs replace neon. Think Harajuku for pensioners.
'I come here twice a week with my friends,' says Hisako Yanagida, 90, in between belting out oldies in a karaoke bar called Songs from the Old Days. 'Meeting and shopping with people my own age helps stop me from going senile.'
Japan is transforming into a 'type of aged society never experienced before', according to a government white paper issued last year. With one-fifth of its 128 million people aged 65 or over, the nation has the largest percentage of seniors on the planet. By the middle of the century, when the average life expectancy for Japanese men is expected to reach 86, and 90 for women, fully one-third of the population will be pensioners.
That inverted population pyramid is already straining Japan's welfare system. But some are finding opportunities amid the nation's worst economic crisis since the second world war. According to the government, the average senior couple has more than 24 million yen (HK$1.8 million) in savings and average monthly spending per household peaks in the 60 to 69 age bracket. Many businesses want a slice of the so-called silver market.
Sugamo is the retail cutting edge of this phenomenon. The 1km main shopping street, Jizo-dori, boasts 10 chemists, half a dozen or more outlets selling walking aids, funeral parlours and a karaoke bar where the song list stops in the 1970s.
