royal road

Short definition from Wiktionary

Noun

1. 1
   An easy or straightforward procedure for achieving a goal; a procedure that requires little effort.
2. 2
   A chord progression, IVᴹ⁷–V⁷–iii⁷–vi, common in Japanese pop music.

Proper noun

1. 1
   The longest road in the ancient system of trade routes and roads developed in Achaemenid Persia, which connected the capitals Sardis (in Asia Minor) to Susa (in Mesopotamia) and featured post-stations with service facilities.