Take three vintage bottles of wine. Ignore every rule about proper storage. Open them about 40 times a year and serve them to whomever you meet. Within moments of tasting them, everyone is certain to experience the same thing: a deep, warm glow guaranteed to last a lifetime.

Such is the feeling that comes with hearing folk singers, activists and humanitarians Peter Yarrow, Noel "Paul" Stookey and Mary Travers, who performed March 5 at Bunkamura Orchard Hall, marking the beginning of their 14th tour in Japan, their 20th album ("Songs of Conscience & Concern") and their 38th year as members of the world-famous musical trio Peter, Paul & Mary.

Graciously agreeing to an interview at the Capitol Tokyu Hotel, PPM displayed the warmth and wit which has infused their music from the outset and established an unshakeable fan base wherever they go.

Looking healthy and relaxed, they finished each other's sentences, joked about themselves and even had a humorous argument about how long it had been since they were last in Japan (for the record, 1995), which Mary settled with a clear "Whatever!"

This is, however, their first tour of the new millennium, having closed the last one with a concert at Carnegie Hall boasting a chorus of 160 voices and a full orchestra.

"There was a joyous sense of coming full circle, toasting to the times we've been together," Peter said. "We've been very fortunate to be together for so long, and I think we are the only group with an international reputation who is here in spirit and form, with all the original members. We still love the music and we are great friends, more so everyday."

That love and friendship is easily confirmed on their latest album. Subtitled "A Retrospective Collection," "Songs of Conscience & Concern" features 14 lesser-known, but equally powerful PPM songs culled from nine of their albums, and one newly recorded tune, "Don't Laugh at Me" (about the name-calling that people who are "different" must endure).

From "Danny's Downs" (about children with special needs) to "Home Is Where the Heart Is" (in which a parent explains gay relationships to a child), PPM remind how they have never been afraid to use their music and words to explore issues and concerns that challenge and touch the human spirit.

"It would have been obvious to put 'Blowing in the Wind' on it," Mary pointed out, "but there were lots of songs that had ethical or humanistic values that were not the well-known songs, so it was great fun to resurrect them and give them a fresh new exposure. And there was something wonderful in the consistency of knowing that these songs still hold up."

Clearly aware of their place in music history, Noel said that what is considered pop music today has obviously been influenced by the folk music of the '60s, pointing out that "there are a lot of things being said both in rap and contemporary pop music that are not strictly boy-girl relationships.

"Time is the greatest instructor in terms of ultimately concluding what is going to be folk music, because, if it exists apart from the media, then that's pretty much the defining line."

It certainly seemed to exist at last Sunday night's concert. With simple acoustic accompaniment (including "fourth member of the trio," bassist Dick Kniss and multi-instrumentalist Paul Prestopino) and their trademark harmonies (strong, clear and untouched by time), PPM brought tears to the eyes of the soldout house with a two-hour show which included their classics, "Puff (the Magic Dragon)," "Leaving on a Jet Plane" and "500 Miles."

After solo turns from Peter, who gently coaxed the audience to harmonize on "Lemon Tree," and Noel Paul mesmerizing everyone with an original composition he played on the koto, Peter reintroduced Mary with, "She's not a day over 35, and yet, she's been with us almost 40 years!" Tossing back that still shimmering shoulder-length blonde hair, Mary invited all to sing along with the spirited "If I Had a Hammer" and the more than ever relevant "Where Have All the Flowers Gone."

Proving it wasn't necessary to just sing an evening of hits to connect with the largely non-English speaking crowd, PPM also performed material from the "Songs of Conscience and Concern" album, including the poignant "Don't Laugh at Me," with its plaintive chorus, "Don't call me names, don't get your pleasure from my pain. In God's eyes we're all the same, one day we'll all have perfect wings."

PPM ended their performance with the Dylan classic, "Blowing in the Wind," but not without Mary pausing to remind everyone, "It's still about peace and justice and all of us working together for those things."

Her heartfelt words were indicative of the passion and conviction PPM displayed throughout the concert and which they have carried with them since their 1962 debut at Greenwich Village's Bitter End coffeehouse.

In a day and age of computerized "idol singers" and fake tarento lip-synching to sound-alike "hits," PPM are unquestionably the real thing.