An advanced chess-oriented crossword

Probably the most difficult of my crossword puzzles so far...

Answers so far:

ACROSS: 5.Opposition, 6.Fine, 7.Blackburne, 9.Transpose, 11.Archangel, 12.Chess, 13.Meran,

DOWN: 1.Muzio, 2.Goteborg 3.Descriptive, 4.Zandvoort 8.Kempelen, 10.Evans

1 Down reads "A gambit within the King's Gambit."

BTW, this crossword is not that difficult...

5 across is opposition.

 First blood!

9 across is transpose

3 down is descriptive

10 down is Evans

3 down is "Descriptive"...

is 9 across "Transpose"?

EDIT: ... I get credit for 3 and 9!

 All right!

12 across is chess.

6 across is Fine

10 down is Shatner (chess humor).

13 across is Meran... just noticed that one.

Could 1 down be Muzio?

Meran & Muzio are correct!

8 down is Kempelen.

7 across is checkmate

11 across is archangel

 Hint: 7 across is a surname...

Hints:

7 Across: British player, heavy whisky drinker

2 Down: Swedish city, "triplets" refers to games which began identically

4 Down: Where Euwe defeated Alekhine

 Correct! <Blackburne>

2 down hint: 1955 Interzonal was held there.