by softball66 » May 29th, 2006, 9:20 am
This is the "BLACKHORSE" code. BLACKHORSE letters interchange for 0123456789 for each letter in sequence. First two numbers are month, next letter is year. last two numbers indicate the leather from which tanner: 01 is Horween. Hence "BL" would be 01 or January. Third letter "K" would indicate year ending "5" or 85, etc.
Joe