How do you capitalize and punctuate your haiku? What you choose to do is just that—a choice. Your preferences become part of your style, and there’s generally no right or wrong way to do it. Nevertheless, here are some points to consider:
Haiku often captures a moment in time, implying what happened both before and after that moment. To help imply this context of time before and after the poem itself, many haiku poets start with a lowercase letter and avoid ending with a period. This choice suggests that the start and end of the poem are both “open” rather than “closed,” which helps to broaden the poem’s effect.
Haiku are rarely single complete sentences, and are often fragmentary. To signal to readers that they’re not reading a regular sentence, many poets start with a lowercase letter and avoid a period at the end. It is still a good idea to capitalize proper nouns, however, so that lowercasing does not look like a typo (such as “english”) and jar the reader out of the poem unnecessarily.
Haiku traditionally have two juxtaposed parts, with one of the parts spanning two lines in a three-line haiku. To help indicate this “cut” between the two parts, many poems use punctuation, typically an em dash (—) or an ellipsis ( . . . ). The em dash suggests an instantaneous jump from one part to the other, as if the two parts are both happening at the same time. An ellipsis suggests a slight pause, as if one thing happens and then the other. A hyphen (-), double hyphen (--), en dash (–), and tilde (~) are not the same as an em dash. Learn how to insert proper em dashes in your software by searching in its Help system. If you can’t insert a proper em dash, use two hyphens, which are typically converted to an em dash when published. Don’t put spaces before or after em dashes. As for the ellipsis, it can be treated as three spaced periods ( . . . ), three periods with spaces at the start and end ( ... ), and as a single character ( … ), although it’s hard to tell the single character from three periods. Haiku books and magazines typically present the ellipsis with spaces before and after each period, and this is the most common and recommended way for haiku. Use commas in haiku only if they are used the way you would correctly use them in a sentence. Do not use a comma where an em dash would be correct.
As an alternative to punctuation, some poets use no punctuation at all, trusting readers to interpret the grammatical independence of the poem’s two parts to make it clear that there’s a “cut” from one part to the other. Other poets sometimes indent one or more lines to indicate the cut or to create other desired effects.
You can vary any of your choices in capitalization and punctuation to suit individual poems, for best poetic effect.
If haiku is like a finger pointing to the moon, you don’t want any jewels on the finger to distract readers from seeing the moon. By considering and standardizing your capitalization and punctuation with the preceding thoughts in mind, you can help each of your haiku point to the moon as directly as possible without any distracting “jewels.”
Note: If you type your haiku in software such as Microsoft Word, the software automatically capitalizes the first word of each new line or sentence. To turn off this default setting, type a lowercased word and then a space (this will automatically capitalize the first word at the start of a new paragraph). Hover your mouse over the first letter that Word capitalized until you see AutoCorrect Options for the change it made. Click the downward-facing arrow, and then click “Stop Auto-capitalizing First Letter of Sentences” (or an option similar to that). Make the choice to be in control of your capitalization and punctuation in haiku.
Another Note: The word “haiku” is both plural and singular, so there’s no need to say “haikus.” Also, the word is not a proper noun, so there’s no need to capitalize it, either. For those who are well established in the English-language haiku community, seeing any use of “haikus” or unnecessary capitalization is an immediate sign that someone is probably a neophyte at this poetry or perhaps unconnected to the English-language haiku community.
One More Note: Haiku “are not snapshots frozen in time, but rather, they flow into other moments and meditations. To represent this quality, I have omitted a capital at the beginning and a period at the end for each haiku [I’ve translated]. Indicating a beginning and an end would feel unfaithful to what I believe makes haiku a distinct and wonderful poetic form. The meanings of haiku are also meant to be open-ended.” —Aya Kusch, Cats in Spring Rain: A Celebration of Feline Charm in Japanese Art and Haiku, San Francisco: Chronicle Books, 2022, page 9