RE: Extra tough Christmas chess riddle (#69). / Knacknuss-Weihnachtsschachrätsel (#69).

1. 0-0 Kf5
2. Nd1+ Bf2+
3. Rxf2+ Kg4

First variant:

4. Ne3+ Kh5
5. g4+ Kh4 (5. ... Kh6 6. Rh2#)
6. Rc8 b1=Q+
7. Kh2 Qh1+
8. Kxh1 Qa1+
9. Kg2 Qh1+
10. Kxh1 Nxd3
11. Kh2 Nf4
12. Rh8+ Nh5
13. Rf3 Bd1
14. Rh3#

Second variant:

4. Ne3+ Kh4
5. g3+ Kh3
6. Rh2+ Kxg3
7. Rg2+ Kh4
8. Rc8 b1=Q+
9. Kh2 Qh1+
10. Kxh1 Qb1+
11. Kh2 Qh1+
12. Kxh1 Bd1
13. Rh8+ Bh5
14. Kh2 g4
15. Rxg4#