In Zen, the offering of incense at the temple altar is of the highest significance. Offering the incense is an unselfish act in which we express our conviction of the Oneness with all things and the transient nature of all existence.
In the incense, we see the potential that is in ourselves, just as the incense itself is worthless until it is put to the flame. We know that our lives are useless, too, unless our potentials are fulfilled.
In the incense, we recognize, too, that our lives are just as fleeting as its sweet smoke.
In offering incense, we should walk dignifiedly to the altar, bow in gassho (respectfully with the palms of our hands pressed together) before it, place our offering in the plate, and then take a pinch of the granulated incense (or stick incense) placing it on the burning part of the charcoal.
After placing the incense on the smoldering fire, gassho again in a graceful manner, and return to your seat. (If the Zen Priest is sitting near the altar, it is proper to bow respectfully to him in the same manner which you would in the gassho).
The gassho used during incense offering symbolized the Unity of ourselves, the Buddha and the World. Our one hand is ourselves, and it is placed, palm to palm with the hand symbolizing the Buddha.
Our slight bow at the time of the gassho is a sign of respect we feel for the benevolence of the universe with which we are One.
In the act of offering incense, the true nature of ourselves is expressed.