As use of the Gregorian calendar has become more prevalent in the postwar period, some see the Japanese era system — which has been in use for more than 1,300 years — as unnecessary and no longer relevant to modern society.

Some argue that the gengō system, which initially symbolized what was considered to be the emperor's control of time, is inconvenient compared with the Gregorian calendar. Others say it contradicts the postwar Constitution that stipulates sovereign power resides with the people.

Asked which they prefer to use in their daily life, 39.8 percent of respondents in a Kyodo News opinion poll conducted in January said they want to use both gengō and the Gregorian calendar, while 24.3 percent opted for the former and 34.6 percent the latter.