As a general rule in long suits, bid the higher suit first before the lower one in cases of unequal length. How about in cases when two long suits have the same number of cards? In cases of unequal length, the one with higher value (combine face and suit value) has to be taken into consideration. Let us take a look on how two 6-card suits and two 5-card suits are managed.
First with the 6-card suits: it is advised to bid both suits unless one of the suits are raised by a partner or one can afford to follow the normal rule of bidding the highest value. For example one has the following cards at hand: spade jack, eight, six, five, three and two; heart ace; diamond king, queen, nine, six, four, three and with no cards under the club suit. With these cards, bid one spade. If necessary, bid and rebid the diamonds in later turns. This sequence always presents that both suits are rebiddable. If a partner expresses a preference for spades with only two small spades in his or her hand, one can await the outcome without fear.
Now with the two 5-card suits: the normal rule is to bid the higher-ranking suit first. Later if still needed, one will bid the lower suits. Much later one may even rebid the lower suit. This may get one rather high. One doesn’t mind bidding up to a high level when one have a really good hand, but one must refrain it when one’s hand is of minimum strength.
Here is an example of a set of cards and what can be done: spade king, queen, jack, seven, five; heart five; diamond ace, jack, nine, six, three; clubs six and two. With these cards, bid one spade. If partner responds one notrump or two clubs, one can comfortably rebid of two diamonds. If the partner’s response is however two hearts, one will not bid three diamonds. That would get one too high. One simply bid two spades.
When one’s suits are spades and clubs, one can keep the bidding low by starting with the lower suit.
In a hand composed of spade king, queen, jack, seven, five; heart five; diamond six, two; and clubs ace, jack, nine, six, three, bid one club. When partner reacts with one of the red suited cards, one may bid one spade. In the next turn, one may continue to bid two spades. By doing so, partner should acknowledge one with six clubs and five spades. He should cipher on five of each and a hand of ordinary strength.
It would be not be required to start with a lower suit when one has a powerful set of cards at hand.