What is the difference between "closed form" poetry and "open form" poetry? Please explain.

In terms of
poetry, there are two kinds or forms, based upon the "structure or pattern of
organization" that a poet adopts when writing his verse.

These are
called "open" or "closed" forms. When looking at a poem's form, you can
observe the following; with more than one of these in a poem, there is probably a set pattern.
Look for the rhyme used: it may be end rhyme (where a word at the end of
one line rhymes with the word at the end of another line). There may be a rhyme
scheme (which is a specific pattern of rhyme, such as ABAB,
where each letter represents a sound, and the pattern is followed in a stanza or an entire
poem). The meter is the poem's beat (which is found in sonnets, where, for
example, iambic pentameter is often used: ten syllables in a line, with emphasis on the second
syllable). There may even be stanzas used (which are often groups of four
lines, but not always). There are other elements as well: these are only a few
examples.

When a poem has a closed form, the
poet has adopted a pattern that the poem will follow in more than one area, such as those
mentioned above. As an example, a Shakespearean sonnet is a fourteen-line
poem. It has three quatrains (which are four-line stanzas), it ends with a rhyming(a pair of
lines that rhyme with each other), it follows a specific pattern of rhyme (ABAB CDCD EFEF GG),
and is written in iambic pentameter. In composing this kind of sonnet, the
poet follows these parameters. Other examples of a closed form poem are the traditional , the
tanka, the , the cinquain, and the villanelle.

Note the haiku below. It is
about nature; it has three lines; and, the syllabic pattern (number of syllables) per line is
5-7-5; (note that this is the traditional Japanese
format of the haiku):

The Rose by Donna Brock

The red blossom bends (5)

and drips its dew to the ground.
(7)

Like a tear it falls (5)

In
contrast, the open form poem does not follow
set guidelines. There is no required rhyme scheme, rhyming pattern, or set number of lines in a
stanza. One stanza, for instance may have four lines, as may the second, but a third stanza may
have five lines. A concrete poem is one that is spaced out so that it creates a picture. As an
example, a religious concrete poem might be shaped like an altar. However, for Halloween, a
concrete poem might be written in the shape of a pumpkin or a bat. This may be the only
guidelines present, and it is considered a poem with an open form.

Note the
lack of form (or the "open" form) of the following poem:

American History by Michael S. Harper

Those four black girls blown
up

in that Alabama church

remind me of five
hundred

middle passage blacks,

in a net, under
water

in a Charleston harbor

so redcoats wouldn't find
them.

Can't find what you can't see

can you?