Blank Verse is different from Free Verse in that a consistent recognizable meter is required.
End-rhyme is NOT permitted.
It is stanzaic with stanzas of any length and number.
Generally it is written in Iambic Pentameter.
The following autologic poem by Ruth Poteet, aka Reason on Allpoety shows all you need to know to pen this form.
Pentameter is normal for blank verse
which simply means ten syllables per line.
It does not rhyme which makes it more relaxed.
You write as many stanzas as you like.
The best examples are iambic verse –
where even-numbered syllables are stressed,
but any steady rhythm will suffice
as long as rhyme is missing from the piece.
© Reason – February, 2013