Along with his unlimited scholarly capabilities, Allah the Exalted had blessed him with a remarkable memory. I never saw him with a diary. He used to save his engagements and appointments in his mind and never had any problem with that. He knew the phone numbers of his friends and contacts by heart. During his stay in London, he used to come to my office by about 10 or 11 o’clock very often and asked me to dial a phone number for such and such person. As I went for the directory, he would say that he would tell me the number off-hand. That happened every time he came. To my amazement, he told me that when he was in Britain, the telephone numbers of British friends were highlighted in his mind and when he was in America, the American numbers were highlighted, and the British numbers faded away.
Another amazing thing of this kind was that he could tell the days on different dates of the year offhand. We would look at the calendar to plan an event, but Chaudhry Sahib would calculate and tell the day immediately.
Once I asked him the secret. He said: “When the new year starts, I download the days of a few important and fundamental dates in my mind and use that data to calculate the day on the required date.”