Also known as: 山下サトル
A male character of Kurogane No Linebarrel.
In the manga he is introduced using the Japanese pronoun for 'he' which is, 'kare' appears in Hiragana next to the kanji for 'he' or 'him'; "そして彼が (Soshite kare ga) Yamashita Satoru-kun da." This can be found in the original Japanese manga, Volume 2, page 86. Additionally, "Satoru" is traditionally a masculine name in Japan.
The Wikipedia article (in the Manga/Anime ring) does refer to Yamashita as a girl. However, this mistake was based on an English scanlation of the manga that has proliferated on the Internet. (Info taken from Myanimelist.net)