The Buffalo nickel saw minor changes to the design in 1916. The word "LIBERTY" was given more emphasis and moved slightly; however many Denver and San Francisco issues of the 1920s exhibit weak striking of the word, the Denver issue of 1926 especially; Bowers questions whether any change was made to the portrait of the Indian, though Walter Breen in his reference work on United States coins states that Barber made the Indian's nose slightly longer. According to Breen, however, none of these modifications helped, with the coin rarely found well-struck and with the design subject to considerable wear throughout the remainder of its run. The bison's horn and tail also posed striking problems, again with the Denver and San Francisco issues of the 1920s in general, and 1926-D in particular, showing the greatest propensity for these deficiencies.