The little-known Boxer range of model engines was manufactured in Japan during the years 1949-1954. There were two basic models in the range - a .29 cuin. design which was pretty much a direct copy of the contemporary O.S. twin-stack .29, and a succession of .099 cuin. models which displayed far more design originality. A test of the radially-ported variant of the .099 model (which was likely the earliest version) showed it to be a fine runner having an output of around 0.11 BHP @ 12,000 rpm - nothing spectacular, but a useful enough sports performance by the standards of the early 1950's. This model was particularly distinguished by its unique exhaust collector ring which could be adjusted to direct the exhaust emissions in any desired direction. A later .099 variant featured a far more conventional layout using cross-flow loop scavenging.
For the complete story of the Boxer range, see my earlier article on Ron Chernich's "Model Engine News" (MEN) web-site.