The Visa number is NOT the control number in the upper right of the visa. It is the bold set of numbers in the bottom right of the visa, above the machine readable portion. The visa I am looking at has a visa number that has eight numbers -- with no letters.
The visa number consists of 8 digits (all numerals, no letters) shown in RED. It's in a different typeface, slightly larger than all other characters printed on the visa. It appears in the lower right hand corner of the visa stamp, but not all the way at the bottom; it is normally above the two strings of characters that run all the way across the bottom of the visa stamp from left to right, and just above the petition expiration date, which is shown in the format "PED 30May2012" for example.
This is general information only. It is not intended as a substitute for legal advice, and does not create an attorney-client relationship.