While we hold dear to this important principle, the exception to “Longer First, Higher Rank First” dogma is very important to know and understand.
Here is the condition: your partner opens 1♦. You have the minimum point to bid, but less than 10HCP (or less than 12HCP if you play “2-over-1 game forcing”). So, basically you are forbidden to bid at level-2. And your hand got 6 cards Club and 4 card Heart. For example:
♠K82 ♥QT73 ♦8 ♣K8754 (3-4-1-5, 8-HCP)
In this situation, you need to bid the Heart first: 1♥. And cannot bid Club although it is longer.
Now to make it interesting. Swap the Club and the Spade in the hand above.
♠K8754 ♥QT73 ♦8 ♣K82 (5-4-1-3, 8-HCP)
The reason for both illustrations above is hopefully pretty obvious:
- Bidding level-2 required a 10+HCP hand. (or 12+HCP)
- Finding a major fit (hopefully 4-4) is at a higher priority than finding fit in the minor.
Actually, in this case, another principle is in play as the exception to “Longer First, Higher Rank First”. It is called: 4-cards major up-the-line principle.
So, in summary. “Longer First Higher First” applies in general, except when “Up-the-line” method is in play. No more exception. Just this.