The Tokyo Classified Telephone Directory published in 1951 (Showa 26) was the first telephone directory in Japan with entries listed by business type. The total number of pages was 1,422 and the directory was printed on yellow gravure paper. The directory listed telephone numbers for approximately 133,000 businesses and carried advertisements for 18,000 businesses. The telephone directory's appearance was also smartened up. The size was changed from B5 to A4 and the text changed from two to three columns. As this was before the era of computers, the editing, which included classifying businesses and products, was said to require continuous effort.