Brain Power.

Does working on puzzles without clues e.g, mate in 1, white to move and draw, make your brain work harder ? Is it good for training and useful ?

Good question, I guess it's more realistic to have no hint, and it can't be bad to simulate a real game situation.  Ray Cheng's "Practical Chess Exercises" is such a book where each diagram only reads who is to play and you don't even know if it's a positional answer or a tactic.

But I think traditional puzzles are good too, and I guess it shows through their popularity over all these years.  Yeah it gives hints that are unrealistic to actual game play, but it helps the student focus on a particular area such as mate in 1, mate in 2.  Even by theme such as Reinfelds puzzle book breaking it down into pins and forks.  It helps the player burn a certain type of pattern into their brain.

For example, a beginner going though Cheng's book may be impressed by the idea of a skewer, only to have to wait 100 pages to see an example of it again.

thanks honda, also will it be much harder if you play on both side ?

Not sure what you mean?

Sometimes I've tried solving a puzzle, when the first attacking move is fairly obvious... the only problem being 3 or 4 different defensive tries... so then you're sitting there spending a lot of energy not trying to find the correct idea for the winning side (you already see it) but trying to find the toughest defense so you can prove it works.

Is that kind of what you mean?  I think it's harder when you have to work to find good moves for both sides, sure.

sorry I didn't make that clear, for example, is it 'white to move and mate in 1' but without the clue, you either try and play white first or black first. 

Yeah, that would be really hard :)  Probably not the best for study though, you'd waste too much time trying to figure that out heh.

It definitely helps your game.

I don't like the puzzles where one side has a enormous advantage, and you need to find that difficult to find "mate in 2" (or so). You can find "mate in 3" or "mate in 4" in couple of seconds, and it wouldn't hurt your game, you would win anyway.

I prefer puzzles when youre materially equal or worse, when you really need to play the right move in order to win the game. 

Yes.  I agree with both you and BQ.

I'll add those positions that are unlike a real game.  So when there are 14,000 mate in 3s and I have to find the clever mate in 2 or pieces are scattered everywhere like they'd never be in a real game, I'm thinking to myself, this isn't useful practice.

and unfortunately, you cant rely on puzzles on chess.com (daily puzzle section) as a nice source for a proper brain workout:

http://www.chess.com/forum/view/daily-puzzles/1122010---desperation

They often include suboptimal play from your opponent.

Pandolifini's Chess Challenges ..111 winning endgames, by Bruce Pandolfini. I like it.  Small enough to carry around. 4x6 inches. Points are awarded for seeing the winning move and for analyzing pertinent variations.  

I also enjoy Chess 5334 Problems, Combinations, and Games, by Laszlo Polgar.  Needless to say, this is too large to carry around comfortably. 

 Practically, the human brain is one organ but could be devided into several sub-organs since different parts control different activities of intellect, perception, sensations and everything else. That is why we see beauty in chess game which is purely intellectual game.  Different puzzles serve as different exercises to different parts of the brain.  Both are good for different reasons.  There is indeed a whole lot we don't know about intellect. For example: Common sense have no nerve endings or any other anatomical indicator.   

It's weird though because lots of people,including myself, don't like it when it gives hints. But the other day, when there was something like a mate in 3 or 4, the puzzle was given a different title and yet some people complained that there should have been a hint.

Ok to the peoples who don'k like the dailypuzzles very much because of hints, would you like to see a puzzle,once a week say Sunday, without any hint or clue except who to move ?

yes yes ci ci

 here is it hui

http://www.chess.com/forum/view/more-puzzles/hintless-puzzle-1