The birth of a royal baby is expected to motivate the Japanese to spend 14 trillion yen, providing welcome stimulus to the decelerating economy.

Keiichi Matsumura, deputy chief researcher at Dai-ichi Life Research Institute, a research arm of Dai-ichi Mutual Life Insurance Co., said the birth could motivate grandparents to spend roughly 1 percent of their personal financial assets -- worth a combined 1.4 quadrillion yen -- on their grandchildren.

The estimated additional outlay of 14 trillion yen is a sizable sum when compared with Japan's gross domestic product, which came to 511 trillion yen in fiscal 2000.