The knee-on-belly or knee mount grappling position.
<a href="//commons.wikimedia.org/wiki/United_States_Army" title="United States Army">The United States Army</a>, photographer unknown.
US Army Field Manual No. 3-25.150 Combatives <a rel="nofollow" class="external text" href="http://www.globalsecurity.org/military/library/policy/army/fm/3-25-150/ch4.htm#sec1">Chapter 4: Advanced ground-fighting techniques</a>