On a match box: “Strike Anywhere”.
Kobun’s literal translation of the elements in the word shikantaza strings together as: “pure hit sit”.
Here’s one from “Zen Letters, Teachings of Yuanwu”:
If you want to pass through easily and directly right now, just let your body and mind become thoroughly empty, so it is vacant and silent yet aware and luminous. Inwardly, forget all your conceptions of self, and outwardly, cut off all sensory defilements. When inside and outside are clear all the way through, there is just one true reality. Then eyes, ears, nose, tongue, body, and conceptual mind, form, sound, smell, flavor, touch, and conceptualized phenomena–all of these are established based on that one reality.
(trans. Thomas Cleary and J. C. Cleary, pg 86).
Similarly, here’s one from the Pali Canon, attributed to Gautama the Buddha:
…making self-surrender (one’s) object of thought, (one) lays hold of concentration, lays hold of one-pointedness of mind.
(SN V 200, Pali Text Society V 176)
What is “one-pointedness of mind”?- here’s Yuanwu again:
Once you have been directed by a teacher or else discovered on your own the originally inherently complete real mind, then no matter what situations or circumstances you encounter, you know for yourself where it’s really at.
(Zen Letters pg 48)
“…where it’s really at”, as in:
Be aware of where you really are twenty-four hours a day. You must be most attentive.
(Ibid, pg 53)
When the impact of consciousness opens the ability to feel, and what is felt enters into the place of occurrence of consciousness, then the mind remains waking up or falling asleep even as the place of occurrence of consciousness shifts. Single-pointedness of mind is just consciousness where it occurs, as it occurs.
On a matchbox, “Strike Anywhere”.