In the context of a precision system, the 1D bid is nominally 11-15 high card points and could be one of the following hand types:
- Unbalanced with 3+ diamonds, no 5-card major, no 6-card club suit (balanced hands and minor-major 5422s are opened 1NT)
- 2=2=4=5 or 2=2=5=4
- A semibalanced hand with 6+ diamonds
- A 6-5 (or more distributional) hand with clubs or diamonds as the longest suit, not strong enough to open 1C (note: this hand type may have 0-2 diamonds)
The last hand type makes it difficult to alert completely and succinctly. I don't think it's reasonable to have a 1-minute explanation of such a common bid as an opening 1D, but I want to make sure to inform my opponents of our agreement.
As a secondary question, do you think that this opening is legal under the ACBL general chart (presumably under the rubric of "all-purpose opening bid (artificial or natural) promising a minimum of 10 high-card points").