if you mean the unchecked letters, no it is not obvious and you dont need to do this but they represent examples re the 6 thematic groups. The last 2 letters and the previous 3 were the easiest ones for me.
Sorry, williamseal - I did (literally!) tick off the letters when I checked them and they're now illegible. That's the trouble with newspaper grids - no second chances! (but I know grunger/jigjag will be right - hopefully, one of them will put us straight.)
Hi brendan,
NJ New Jersey - Geography
NCIS telly programme - Entertainment
NAM Vietnam - History
TEXT - Literature
OHM SI Unit - Science
RU Rugby Union - Sport