Have an idea for a Kaiu engineer that's an architect but can't figure out which skill or skills is used for architecture and engineering. The school gives you smithing and design as artisan skills. Now while I can see you somehow shoehorn engineering into smithing (I mean even making a clock work mechanism you probably had to bang pieces of hot metal against each other at one point during the process so you could argue it makes sense. Guess the same could be true for building a bridge.). But even with modern languages incessant use of designer for every remotely creative profession, design in the L5R rules explicitly concerns fashion design so it doesn't really seem to fit architecture. Yet it certainly doesn't fit smithing either.
Of course you always have labour which certainly would work for a carpenter or a potter but architecture or engineering. Not exactly endeavours you think of when you hear the word labour?
Which brings you back to smithing. Yet at the same time you don't want to make it the ad-hoc skill for every technical skill there is.
So which should you use?