There comes a time in every Bridge players life when he or she must play an honor on partner's honor. This type of play is either very brilliant or very dumb; depending on the player not the results.
        The situation where you play a higher honor over partner's led honor is known as OVERTAKING. You are overtaking partner's card with your higher card. Who but a partially deranged Bridge player (the fully deranged play poker) would overtake partners high card? It seems like a terrible waste. Cardiologically unsound.
        There are situations, however, where overtaking is necessary. In Hand 1 North/South are in 3 No Trump. If you do not overtake West's (partner) opening lead of the Q
C, South can hold up the first round. West continues the suit and you are forced to play the K C. South, not a nice person, holds up again. Now you have the lead; no more Clubs; South retains the A C; and you have no way to get to West's hand.
   hand 1                                              
C  7 4 2

    WEST                      EAST (you)
C  Q J 10 9 3              C  K 7            

C  A 8 5
Your helplessness is causing steam to rise from your partner's head and you can tell from his expression that he wants to strangle you. If on the other hand you overtook partner's Q C with your K C and shot back your 2 C, West would win the second round and play a Club forcing out South's Ace C.

Hand 2 you must overtake partner's K S with your A S. This might raise an eyebrow or two, but you will redeem yourself by playing the 5 S enabling partner to play a third round in that suit. If you are defending a No Trump contract partner has to have a three card sequence for that lead. That is K Q J or K Q 10.
   hand 2                                              
S  6 4 3

    WEST                      EAST (you)
S  K Q 10 8 2            S  A 5           

S  J 9 7
In a suit contract you will be able to ruff the third round if partner started with K Q x. If you do not overtake, you will have to win the second Spade trick. West's hand might be unreachable.

There are times when overtaking is obvious, but perhaps too obvious because many players through oversight, greed or fear will not do it. In
Hand 3 you have bid Hearts and South gets to 3 No Trump. West leads the J H. You must overtake and continue the suit. If you do not overtake, South holds up and partner is on lead but has no more Hearts. She doesn't look very happy.
   hand 3                                              
H  7 5 4

    WEST                      EAST (you)
H  J                       H K Q 10 9 2           

H A 8 6 3

Now that you are in the overtake mode, let us look at a situation where it is best not to overtake. This is when overtaking can cost a trick.

   hand 4                                              
D  10 6 4

    WEST                      EAST (you)
D  Q J 9 8 2             D  K 3           

D  A 7 5
In Hand 4 above it is obvious. If you overtake partner's Q D with your K D and Declarer South has the A D, then the 10 D in Dummy will become a winner.

   hand 5                                              
C  8 6 3

    WEST                      EAST (you)
C J                        C  K Q 10 8 5          

C  ? ? ? ?
In Hand 5 it is not so obvious. If you overtake and Declarer has the A 9 x x, the nine will eventually be a winner. Play safe, do not overtake. Signal with the 8 C.  Hope partner has a second Club.