This card appears to be based on the right half of a Torii gate, a traditional Japanese gate most commonly found at the entrance of– or within –a Shinto shrine. These gates are intended to symbolically mark the transition from the profane to the sacred in these temples, and come in a variety of forms and materials.
Fittingly, this monster has a blue-faced counterpart which forms the left half of the gate; "Yosenju Shinchu L."
Its name literally means "right sickle god pillar".
The ogre-esque face featured on this card could be a reference to the classic "Red Oni, Blue Oni" trope featured in many works of fiction.
A character shown as a Red Oni is associated with passion, wildness, and defiance. A red oni character is often more brawny than brainy, extroverted, enthusiastic, determined, and filled with a zest for life. He is also much more likely to break conventions and rules than his counterpart. Often an Idiot Hero or, in more mature pieces, a Boisterous Bruiser. If a red oni is indeed noticeably intelligent, he will still be much more emotional than the blue oni and/or with less sophisticated thoughts, feelings, or goals.
The use of the "Red Oni, Blue Oni" trope on "Shinchu R" and "Shinchu L" likely also reflects the left and right Pendulum Zones, which share the same blue-red dichotomy.