It warms my heart to see such public displays of genuine affection between siblings in this crowded metropolis. Representative of the rapid urbanization across the globe, some 13.5 million people now live in Tokyo. Yet even as Tokyo grows, Japan's population is shrinking by around a million people annually with no end to the fall in sight. As fewer Tokyoites have children, I wonder how rare such scenes may become if the current population of 127 million falls to 42 million by 2110 as projected.