Dr. Yoshimaro Yamashina (1900–1989) was a Japanese ornithologist and the founder of the Yamashina Institute for Ornithology. His two-volume “A Natural History of Japanese Birds,” published in 1934 and 1941, was an important contribution that greatly influenced the development of Japanese ornithology. We have previously published “The Cataloging and Preservation of Manuscripts, Prints, and Related Materials Used for ‘A Natural History of Japanese Birds’” (Tsurumi et al. 2014). However, in 2016, additional materials relating to these volumes were found in the Yamashina Institute for Ornithology and at Dr. Yamashina's former residence. These additional 294 items were registered to the Institute's collection, and consisted of 116 original drawings, 157 trial prints and one picture, eight manuscripts, and 12 miscellaneous items such as errata slips and envelopes, increasing the entire collection to 821 items.