Is there an archive of harder problems?
Not exactly but you might look here:-
And if you're really up for a challenge, try this one (it's only recently been posted) but be warned - it's a tough one:-
Of course if you just want to search the Daily Puzzles archive, just click on 'Daily Chess Puzzles' in the top-left of this page & it will link to it. Then you have access to about five years (?) of puzzles from this site - that should keep you busy
nice and great for sunday
Can anyone say obvious?
Now THAT was hard !?
easy, very easy!!!
That was my game I won last week!
where is the puzzle????....
easy, the bishop is very helpful though