Wafū wrote:

Chō kiete    tamashii ware ni    kaeri keri
Butterfly having-gone    spirit me to  returned

The butterfly gone,
My spirit
Came back to me.

What does he mean?  He means that he was so absorbed in watching the butterfly that he and the butterfly became one, and Wafū lost consciousness of himself and was only — for a short while — the flitting, fluttering butterfly.  Then the butterfly was gone, and Wafū suddenly “came to himself” as we say in English.

This happens all the time.  Watch a child reading a good book.  The child forgets himself or herself, becoming the action in the book.  Then a shout from the mother brings the child back “to the body,” back to our customary separation of subject and object.

This subject-object unity is the very essence of hokku.  In hokku the writer — we do not even want to be so grand as to say “poet” — disappears in the presence of what is happening in Nature.  When he looks at a tree, he becomes a tree; when he looks at a rock in the stream, he becomes the rock and the water swirling about it.  He forgets himself for the moment, and that is not only how hokku takes place, but it is also one of the most important ways in which hokku differs from conventional Western poetry, particularly modern English-language poetry, in which writers seem so desperately self-obsessed.

Wafū’s verse, then, has something important to teach us about hokku.  Technically, however, it is just a simple “standard” hokku in form, consisting of a setting, a subject, and an action:

Setting: The butterfly gone,
Subject:  My spirit
Action:  Came back to me

Remember that a setting is the wider atmosphere, environment, or circumstance in which something takes place.  The subject is what we “focus” on in that atmosphere, environment, or circumstance, and the action is something moving or changing, however quickly or slowly.  One can write countless hokku using this “pattern” and the old hokku writers did.  Remember that setting, subject, and action need not be in that order.

One has to be really careful in writing hokku about a “delicate” subject such as a butterfly.  It is easy to fall into sentimentality or “prettiness,” both of which are death to hokku.

Shiki, for example, wrote a really awful “haiku” on the butterfly:

Butterfly sleeping on a stone,
You will dream
Of my unhappy life.

Well, no it won’t.  The butterfly could not possibly be less concerned with Shiki, and Shiki should have concerned himself more with the butterfly.

There are unfortunately more bad verses written by old Japanese authors on the dreams of butterflies, but we have no reason to add to the smelly pile.  Instead, we should write more objectively, as did Buson:

Tsurigane ni   tomarite nemuru   kochō kana
Temple-bell on  having-perched sleeping  butterfly kana

On the temple bell,
A butterfly has settled,

Now on the surface there is not much to this.  But the whole point of the verse is in knowing that the temple bell is a very heavy, cast metal object that is struck at certain hours of the day by a long, horizontal swinging pole; when struck, it emits a great, deep BBbbboooooooooooooonnnnnngngngngngng that vibrates not only the whole bell but all the air around it, sending out a sound that can be heard for a great distance.  From that the perceptive reader will gather, correctly, that this is a hokku of “harmony of contrast.”

Remember that there are hokku made by combining similar harmonious elements, but there are also hokku made by combining contrasting elements that when put together still make a kind of overall harmony.  That is the case in this verse.  The contrasting elements are the great, dark, heavy bell and the very small, very fragile, butterfly.  The butterfly is always silent; the bell is silent only for the present.  When struck, it will vibrate with great energy, and the butterfly will flutter away.  We are to sense all of this when we read the verse, but to say it really spoils it.  Nonetheless in teaching hokku, one has to explain such things until a student develops a “hokku” spirit and begins to understand them for himself or herself.

Garaku composed a hokku that shows us the nature of the butterfly:

Even chased,
The butterfly is not
In a hurry.

Try to catch a butterfly, and it will just casually, apparently thoughtlessly, slowly flutter away, pause, and flutter off again at its usual, leisurely speed.

Sora too wrote a “butterfly” verse:

Back and forth,
Stitching the rows of barley —
A butterfly.

R. H. Blyth, however, improves on it by removing the “stitching” simile, which I shall also do here:

Back and forth
Between the rows of barley —
A butterfly.

Why does that improve it?  Because the butterfly is not really “stitching,” just making a back and forth, to and fro repetitive motion.  Butterflies do not “stitch,” and when we use such a word, it takes us just that much farther away from reality.