We call this symbol the "Peace Mark."  This mark symbolizes Honbushin's teachings.

The big circle represents Kamisama's blessings.  Everything in this universe was created by Kamisama through many evolutions.  We are able to live today thanks to these blessings.  The teaching says that, everything in this world is operated by Kamisama.  It is okay to refer this operator as Kamisama, nature, or even as universes great providence.  Either way, we are surrounded by some great power that exceeds human beings, and that is what the circle symbolizes.  The vertical line inside the circle represents you, yourself.  The horizontal line represents everyone that supports you.  In other words, you are able to be here today thanks to the blessing of nature and all the people that supports you.  Thank you very much.  That's what this mark symbolizes. 

 "Mother nature, thank you!  Everyone, thank you!   I'm here, thanks to you!