The phrase "opening wedge" implies a tool or object used to create an opening or gap. There are several synonyms for this phrase, including "wedge tool," "starting point," "initiating step," "key element," and "first move." Additionally, the phrase "opening strategy" could be used as a synonym. This phrase refers to the initial steps taken in a process or plan to create an opening for further action or development. Other related terms include "entry point," "pivotal moment," and "gateway," all of which connote a beginning or starting point for some larger action or process.