Cash is king in Japan, and more so for the country's fast-aging population who are still deeply reluctant to give it up.

Prime Minister Shinzo Abe's push to make more Japanese — the world's most dedicated cash-hoarders — switch to using cashless payments is producing some success, but not nearly as much as desired. Growing ranks of the nation's elderly pensioners are resisting change, which could see Japan fall further behind its peers in adopting mobile app payments and electronic money.

Tokyo wants to double the ratio of cashless settlements to 40 percent by 2025 and to 80 percent eventually to spur labor productivity. Japan pales in comparison with other countries — 96 percent of transactions in South Korea and 66 percent in China are cashless, data from industry lobby Payments Japan Association shows.