There was a similar topic recently on China and I was confused trying to tag my Japanese question so I figured this could be helpful.
Presently, Japan-classed tags include japan, classical-japan, medieval-japan, and tokugawa-era. I would have wanted to tag my question (relating both to the Restoration in a narrow sense and to later internal politics in a broader one) as "meiji-period" or "meiji-japan" but these tags do not exist. Neither do comparable options for the Taisho, Showa, or Heisei -- yet, a tag exists for meiji-restoration which is a very specific time limitation (1868 to 1871 if we count the abolishment of the domain system as its end) but at least some of the questions actually span the later Meiji period (1868–1912).
Is this simply because of a dearth of questions? If so, could a policy still be determined such that questions -- when they appear -- can have the most informative tagging from the get-go?