JR, r.w. means relative bearing. I am sorry but I don't know the German (but would like to if anyone knows as this abbreviation is a common entry in KTBs).
Gegnerlage (or simply Lage) translates as target angle - the relative bearing of the U-boat from the target - usually given in degrees green (grün - gr.) meaning starboard or red (rot- r.) meaning port or Bug links/rechts (bow left/right)
You can see a couple of examples at: [uboatarchive.net]
The first page from U-96 shows the use of r.w. and the second from U-109 shows the use of Lange r and l Jerry