With trips to Japan being so popular among people from Hong Kong, Tokyo sees the territory as a testing ground for trying out various initiatives and analyzing behavioral patterns as it seeks to attract more foreign tourists.

A record 2.2 million Hong Kong residents visited Japan in 2017, up 21.3 percent from the previous year, according to the Japan National Tourism Organization. This means that more than 1 in 3 people from the Chinese territory have visited Japan, and almost 21 percent of them have done so more than 10 times.

"There is nowhere else that resonates as much as Hong Kong. The locals really like Japan and have deep knowledge that even we Japanese don't have," said Yasumasa Shimizu, JNTO's senior director of the Hong Kong office, citing as an example the popularity among Hong Kong people of the relatively obscure Iya spa resort in Tokushima Prefecture.