Gudo Nishijima didn't do any chanting at his meetings or retreats. He preferred to just stick to zazen and afterwards give a talk and answer questions. Sometimes someone would ask why there was no chanting. Nishijima usually answered that he liked to follow Master Dogen’s ideas on Buddhism, and he felt Dogen didn’t particularly recommend us to chant as part of Buddhist practice. If he was pressed a bit on the subject, Nishijima would quote something or other Dogen wrote about chanting that indicated his preference for zazen. If you've read the Shobogenzo a bit you might have come across one or two passages on the subject.
But there are always exceptions. In Nishijima’s case, the exception to his chanting policy was the Heart Sutra. He used to chant this once each day after early morning zazen at his dojo
The Heart Sutra is a discussion between Gautama Buddha and his disciple Sariputra about something called “prajna”. Prajna is a Sanskrit word. The first part pra means “before” or “prior to”. The second part jna means “knowledge”. Nishijima usually translates prajna as “intuition”. A lot of people translate it as something like “real wisdom”. Whatever way you want to translate it, prajna is referring to something that’s completely different to what we normally consider to be knowledge or wisdom. We usually assume that we accumulate knowledge by studying or learning. But with prajna it’s a bit different. Buddhism says we develop prajna by practicing zazen. I know that sounds a bit strange, but that’s the Buddhist idea.
Another thing about prajna is that we don’t have any particular control over it. It’s either there or it's not. Sometimes we get a glimpse of it and sometimes we don’t. But if we get a few glimpses of it or experience it a few times we can get a feel for what it is. If we don't get a glimpse of it or notice it at all, it's a bit harder to believe such a thing actually exists.
Like I say, the theme of the Heart Sutra is prajna. Below is one part where the Buddha says that bodhisatvas rely on prajna. It’s a nice idea. To me it suggests that if you practice zazen everyday you can rely on prajna to help guide your actions. Mind you, it's not quite as simple as that, and sometimes we mess up, but the idea at least seems to be like that. Of course, the hard part is trying to rely on something you can't see, hear, touch, taste, smell, or even grasp mentally. But that's Buddhism for ya. Anyway, here's that part where the Buddha says bodhisatvas rely on prajna:
With nothing to attain,
rely on prajna-paramita,
and their minds are without hindrance.
They are without hindrance,
and therefore without fear.
Far apart from all confused dreams,
they dwell in nirvana.
All buddhas of the past, present and future
rely on prajna-paramita,
and attain full, complete realization.
Therefore, know that prajna-paramita
is the great transcendent mantra,
the great bright mantra,
the supreme mantra,
the unequalled balanced mantra,
that can eliminate all suffering,
and is real, not false.