user1315: as I know that certain opening will leads to certain positions, but I do not know if certain opening will determine relative value of chess pieces. Are there some sources to explained it??
as example :
if I choose Ruy Lopez, my knights will more worth than my bishops, and etc.

user933: To some extent, yes. General rule: if certain opening/variant of opening will leads to open position, then bishops will be worth more than knights - and usually opposite in closed games.

1315: <p>as I know that certain opening will leads to certain positions, but I do not know if certain opening will determine relative value of chess pieces. Are there some sources to explained it??</p>

<p>as example :
if I choose Ruy Lopez, my knights will more worth than my bishops, and etc.</p>
 933: <p>To some extent, yes. General rule: if certain opening/variant of opening will leads to open position, then bishops will be worth more than knights - and usually opposite in closed games.</p>
