To cite package ‘washoku’ in publications use:

  Uryu S (2024). _washoku: Extra 'recipes' for Japanese Text, Date and
  Address Processing_. R package version 0.0.0.9000,
  <https://github.com/uribo/washoku>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {washoku: Extra 'recipes' for Japanese Text, Date and Address Processing},
    author = {Shinya Uryu},
    year = {2024},
    note = {R package version 0.0.0.9000},
    url = {https://github.com/uribo/washoku},
  }