This 128-page Japanese magazine, "博文館発行 日露戦争実記 （第七拾参編）" (The True Record of Russo-Japanese War, published by Hakubun-kan, Vol. 73), was published on June 3rd 1905. It referred to Liancourt Rocks in the text (p.7) as "リャンコールド岩" (Ryankorudo-gan) although it had been officially incorporated into Shimane prefecture and had been named as Takeshima in January that year. The magazine included a sheet of paper as a supplement which consisted of three different maps. One of them labeled Liancourt Rocks as "リアンコールド島" (Riankorudo-toh or Riankorudo island) and another one labeled the rocks as "リヤンコルン岩" (Riyankorun-gan). These different names for Liancourt Rocks may indicate that the rocks were not familiar to Japanese people yet.
As Kaneganese already pointed out in another posting, Navy also didn't use the name of Takeshima during the battle. It means that apparently, for Japanese officials, Navy, especially Admiral Togo and his brains had not placed much importance on incorporation of Takeshima from the strategical point of view. Pro-Korean scholars used to say that Japan "annexed" Laincourt Rocks to use the rocks for military reasons, but it was not true.