I don't know how many times is enough, but I think it would need
some period of time of sincere and consistent practice. You can
proof the effects if you are sincere in your practice, and
consistent. If attaining Buddhahood or remember past lives is that
easy as to simply give offering once, then I think all Buddhist
practitioners can remember past lives or attain enlightenment by
now.
BTW, you may want to check out this sutra, though it's not
Ksitigarbha Sutra but it shows what happens (signs) if a
practitioner chant a specific number of times (like, 200000,
300000, 600000, 800000 etc). The minimum would be 4320 for some
kind of ritual where you will see the appearance of the buddhas and
bodhisattvas. Otherwise you need to chant a few hundred thousand
times in order to clear off your karma, and so on, and there will
be visions appearing to you to confirm that you have accomplished
that. (See the URL)
http://yzzj.fodian.net/World/cundi.html
Hmm, since you don't know how many times is enough, so can I
assume that you have not yet personally tried out what is taught in
the sutra on achieving those benefits? (chanting/making offerings
etc) But anyway thanks for giving me the link. :)
I wish to quote the below from Sutra of Ksitigarbha
Bodhisattva's Original Vows:
"Moreover,
Contemplator of the World's Sounds Bodhisattva, in the future, good
men or good women may have to enter mountain forests, cross over
rivers, seas, or other large bodies of water, or take dangerous
routes either for the sake of earning their own livelihood, or for
public or personal affairs, or matters of life and death, or other
urgent business.
Such people should
first recite the name of Earth Store Bodhisattva a
full ten thousand
times. The ghosts and spirits of the lands they
pass through will then guard and protect them in their walking,
standing, sitting, and lying down.
The peace and
happiness of those people will constantly be preserved, so that
even if they encounter tigers, wolves, lions, or any other harmful
or poisonous creatures, they will not be harmed."
They should place a
bowl of pure water before the Bodhisattva for one day and one
night.
Afterwards, placing
their palms together, they should state their request and then,
while facing south, prepare to drink the water. As the water is
about to enter their mouths they should be particularly sincere and
solemn.
After drinking the
water they should abstain from the five pungent plants,
wine, meat, improper sexual activity, false speech, and all killing
and harming for one to three weeks.
"In dreams those good
men and good women may then see Earth Store Bodhisattva manifesting
a boundless body and anointing the crowns of their heads with
water.
When they awaken they
may be endowed with keen intelligence.
From the above quotes, I wonder if I
can infer that ten thousand
times would be the bare minimum
for chanting and in addition they should abstain from five pungent
plants, wine, improper sexual activity, false speech and all
killing and harming in the process?