What is better : bishop or knight ?

I was wondering is it good to exchange a bishop for a knight? Does it depend on you level, also?

It depends on the position. The general view is that knights are better in closed positions. Bishops are better in open positions.

I know that but what about in openings like the Ruy Lopez?

Bishop imo

THE KNIIIIIIIIIGHT

Definitely the knight, because he can make the one move that the queen can’t make.

A person who wields a "long knife" is a strategist. In bronze-age languages, sword must be two-edged, so they use knife for "one-edged sword". In medieval-age languages, a sword has a pommel act as a nut and the end of the tang as a bolt; a knife has its handle riveted to the tang. A Japanese sword is a German knife.

assuming that you are not a master at tactics (since you are asking this) you just need to know basic principles of material values.

• they are both 3 points of value
• bishops are considered to be more powerful in open positions, mostly in endgames.
• knights are considered to be more powerful in closed positions.. like in the opening phases. that's why you are advised to develop your knights before your bishops.. 
• bishops and rooks are more powerful when you have them as pairs. knight pairs are good at protecting eachother.
• knights are also good blockaders of passed pawns since they can block a pawn and attack one of its defenders (another pawn usually)

thats all there is to it. now you have the wisdom, go and spead the word loL

It is largely positional and conditional on the stage of the game. A bishop loses value when your pawns are locked into chains on its own color; is smothered or inactive. I find a bishop is most powerful late in the opening and middle game when long diagonals appear.

In the endgame, I would almost always prefer a knight do to its ability to threaten any square on the board with enough moves. A bishop, although it can threaten more squares at once, can only threaten half the squares.

I would also say that knights inflate in value against less experienced opponents. Forks threats don't occur on a predictable, diagonal line and can therefore be difficult to perceive. Playing against a novice, your knight can very often trade against a major piece in devious fork attack.

It depends on the position. But knight and bishop are roughly equal.

knights are hard to take but bishops can take pieces with lots of mobility

In space the Bishop is better as it covers more space, however the knight is better in situations where there are notar

Knight

*not as many open spaces

innerdarkness23

I think the knight is just better overall

SeaWing7000 said " I know that but what about in openings like the Ruy Lopez?" In openings like the Ruy Lopez, I assume that you are referring to the move order, 1.e4,e5 2.Nf3,Nc3 3.Bb5,... and black responds with 3. ...,a6. Black basically puts the question to White as to whether he wishes to trade the light squared bishop for the knight on c6. Or retreating the bishop to be used in later stages of the game. The move order is generally 1.e4,e5 2.Nf3,Nc6 3.Bb5,a6 4.Ba4,b5 5.Bb3,Nf6 6.c3,Be7 . In simple terms, you can play either line. I personally think that retreating the bishop is the best option. With the bishop on c2, it possess a good diagonal attack against blacks castled king. The exchange line ( 4. Bxc6,...) i feel releases the central tension too soon. Some beginners play the exchange line because they falsely believe that they win the e5 pawn by playing 4.Bxc6,dxc6 5.Nxe5, but Qd4! attacking the knight on e5. The knight retreats to f3 and the black Qxe4 with check. The Queens are exchanged for an even position.

Knights fork, bishops skewer