Literally "edge". Finnish Military Jargon for

  • something that was done exactly by the book, or
  • someone who always does everything by the book.

Ruotuväki newspaper 17/2001 (2001-09-19) says this, but I to be honest, have my doubts on this etymology =) The article was about "Särmä" insignia: A shield-shaped green, silver-edged badge with blue/rose diagonal rectangle (that looks like bed cover folded to neat rectangular pile - so called "pinkka").

The "Särmä" badge has long traditions, all the way to World War I France. The "black sheep" of Knuutti family, sir Sampsa "Särmä" Knuutinpoika, decided to arrange the bodies to neat north-south rows on the bloody battle field of Verdun.

The sewing instructions for the badge are also rather edgy: The blue color of the pinkka is rosé-shaded ultramarine and the thread is Prussian wool thread, diameter 0.32 mm. The size of the badge is approximately 48.77 mm x 55.42 mm and it's attached to the sleeve at 217.2 mm from the left elbow up towards the head.

I have no idea where the term actually comes; other than the fact that in the army everything that's done "by the book" has certain amount of "straight edges".