"Religious cultivation was carried furthest, perhaps, by devotees of the
Tantric or Esoteric sect (Mi-tsung).  During the Republican period,
Tibetan lamas had almost as much of a cachet in China as they had in
Europe - and for similar reasons.  Rich laymen became their desciples to
get their instruction in the exercise of paranormal powers.  Others went
to Japan to study Tantrism in its Japanese form of Shingon (Chen-yen). 
Not all Tantric masters had been ordained.  Some were laymen who after
studying under Tibetan or Japanese monks took disciples themselves."

_The Practice of Chinese Buddhism, 1900-1950,  by Holmes Welch, pgs. 385-6.


"Although...a Tantra of desire flourished in India and Tibet, its
teachings were less appealing to Buddhists in other countries....  In
Japan, however, there was one sect that went as far, if not further than
any Tantric school in India, China, or Tibet:


"One of the patriarchs of the Tachikawa-Ryu was Monkan.  For more than
two decades Monkan had faithfully observed the monastic precepts; he had
read every volume of the enormous Buddhist canon, debated with the most
learned doctors, subsisted on the thinnest gruel, and spent years in
solitude, meditating each day on the vanity of existence.  Still,
nothing could quench his inner fire and the desire for passionate human
love.  One night a dakini appeared to him in a dream and said, 'You must
learn to experience the Great Bliss, the union of a man and a woman. 
Liberation can only be realized through the act of sexual love.'

"Thus Tachikawa texts state unequivocally, 'Buddhahood resides in the
yoni of a woman.'  'If you are afraid to embrace a woman (or man) you
will never become a Buddha.'  'Sexual intercourse is the supreme
Buddhist activity.'  The boudoir, not the temple or the meditation
platform, Tachikawa masters proclaimed, was the best, indeed the sole
place to win enlightenment....

"...Ejaculation was terms the 'Assembly of Dragon Flowers,' while female
lubrication was known as 'Diamond Lacquer.'  (Ejaculation, incidentally,
was not as widely discouraged in the Tachikawa texts as in Indo-Tibetan
Tantric literature; the Tachikawa maintained that ejaculate was a shower
of love that contained thousands of potential Buddhas.)  The male
partner was perceived as Fudo Myo-o, the Immovable One of fierce
intensity who bears the flaming sword of wisdom; the female partner was
Aizen Myo-o, the goddess stained with love, not confused by or afraid of
sex but open to all its splendor.

"The mandala of the Tachikawa-Ryu was a couple engaged in ritual
intercourse.  Since the mingling of the cosmic elements was the supreme
act of worship, the school denounced autoeroticism and homosexuality as
sterile and counterproductive.  Participants in Tachikawa rites wre
encouraged to transform themselves into enlightened beings and were
therfore instructed to first manifest the physical form of male and
female Bodhisattvas.  Tachikawa texts delineate  beauty exercises for
women practitioners.  The buttocks, for  instance, can be shaped into
lovely half-moons by doing special prostrations and leg raises in which
the woman imagines herself walking on air or fluttering through the sky. 
To enhance the breasts, one should place the hands together in the
gassho posture of worship and expand the chest muscles.  Men were
similarly counseled to strengthen the body and sex organs through yoga
and to develop restraint through breath control.

"Before reenacting the union of Buddha with his Consort, the
practitioners thoroughly washed themselves and anointed each other with
scent.  Their temple was the boudoir, adorned with the best Buddha-image
of all - their naked bodies.  Intercourse itself proceeded slowly and
reverently; it was suggested that the ritual begin at midnight and not
reach climax until the  first crow of the rooster.  During sexual
congress, the breath should be harmonized according to the a (in) un
(out) rhythm; the optimum beat is eight (or nine) shallow strokes
followed by one deep thrust.  'Turning the Wheel of Dharma' was
recommended as an excellent means to circulate the vital juices,
allowing the partners to savor each other's nectar.  The instant of
orgasm was the moment of truth, a state of pure bliss, an unobstructed
blending of emptiness and form, the Jewel in the Lotus - all hail!

"Tachikawa apologists claimed that its sole purpose was to elevate men
and women from base animals to enlightened beings, a fulfillment of the
Buddhist scheme of universal salvation.  Most couples, they contended,
are caught up in their own delusions and so are usually totally ignorant
of each other's real feelings even in sexual intercourse.  In the
Tachikawa-Ryu, couples were enjoined to always attempt to be in mutual
accord, to worship each other as precious jewels and rare flowers.

"Unrestrained indulgence in sexual intercourse was never advocated by
the Tachikawa-Ryu.  Fast days and periods of abstinence were mandated. 
Sex must be avoided in the following cases: just after menstruation and
other inauspicious times; when either parner has skin eruptions; when
either partner is in mourning; when either partner has a high fever; and
when the female partner is pregnant or in mental distress.  Since the
sex drive must  be sublimated until it can be used properly, yoga
exercises for self-control were taught to Tachikawa practitioners.  For
the Tachikawa teachings to be truly effective, these conditions must be
present: the couple must have faith in, and carefully observe, the
principles of the school; they must be in total accord with each other,
emotionally as well as physically; they must not overeat or -drink
(sic); they must not argue; and they must not conduct unauthorized rites
or experiments.

"Despite the seemingly noble aims of the Tachikawa-Ryu, it was condemned
and persecuted by rival Buddhist sects and the conservative Samurai
authorities.  The Tachikawa-Ryu did have some grotesque features -
worship of skulls (coated with effluvia of sexual intercourse, the most
potent potion there is) and horse penises, for example - and many of its
professed adherents lacked the proper discipline, engaging in orgies and
black magic.  The Tachikawa-Ryu went underground and was finally
suppressed.  But it was not forgotten, and the cult still has devotees,
in different guises, in modern Japan."  

_Lust for Enlightenment, pgs. 80-84.