A vav-conversive (also called a “vav-consecutive”) is a conjunction and is usually translated “and”.  It is easily distinguished from a simple vav conjunction since it always has a vav with a patah under it and a dagesh in the following letter.   more

וְשָׁמָֽיִם a simple vav conjunction

וַיִּיצֶר a vav-conversive

The key point to remember is that a vav-conversive converts a YQTL from a future tense to past tense (these forms are often called a “preterite”).  The following rules are helpful for identification:

  1. It is only ever added to a YQTL verb.
  2. The dagesh from the vav-conversive will never appear in the first letter of the verb.
  3. A vav-conversive will shorten a verb every chance it gets (KHW 32.3a). See the third-ה paradigm for an example (KHW p448).