1985 marked the end of the era of Gygaxian Dungeons & Dragons and few products show this more clearly than Oriental Adventures, which, despite Gary's byline on its cover, was largely the product of others whose visions of the game would carry it into the Silver Age and beyond. I first recall having read about OA a couple of years before its release, when Gygax commented that he felt classes like the ninja and samurai -- and even the venerable monk -- didn't really belong in "standard" D&D, being best reserved for a book that better placed such classes in their "proper" cultural context. At the time, that seemed like an appropriate point of view, very much in keeping with the tenor of the Silver Age, which concerned itself with "realism" of all sorts, including the cultural.
Being an unrepentant TSR fan boy in those days, I eagerly awaited the release of Oriental Adventures and snagged it before it was widely released in my area, thanks to a comic store that got its sole copy of the book before it was on bookstore shelves. And I'm not ashamed to say that, at the time, I loved every bit of it, including its martial arts creation system and its non-weapon proficiencies. Just about everything about OA matched up well with my own burgeoning Silver Age sensibilities. I wanted my D&D campaigns to be as realistic as possible and OA seemed to deliver that, for its fantasy was (generally) more well-grounded in Asian history, legend, and folklore than was Western D&D, whose source material was an eclectic mish-mash assembled haphazardly by accretion than through any rational plan. Judging by the success of Oriental Adventures -- it was TSR's biggest seller in 1985, surpassing even Unearthed Arcana -- I wasn't the only one who appreciated the book's approach.
Oriental Adventures is a very clearly a product of late 1e. It replaces very few rules from the earlier volumes of the line, opting instead to expand and embellish existing rules. Likewise, everything within its pages are presented within the context of the larger AD&D rules set: Samurai are a sub-class of Cavalier and Wu Jen are largely Magic-Users with a unique list of spells, little different than Illusionists on the mechanical level. And the Ninja is a complicated mess, a kinda-sorta dual class every bit as complex -- and over-powered -- as the Bard. There are rules for generating a character's family (randomly, of course), as well as calculating the acquisition and loss of personal Honor. The monetary system is flavorful but convoluted and the choice of weapons and armor is even more exhaustive than in standard AD&D. Throw in the aforementioned non-weapon proficiencies and you have nearly the Platonic ideal of a Silver Age rules supplement, marrying cultural depth (though not as much as in Bushido) to the full baroque splendor of late 1e.
I still have a lot of nostalgia about Oriental Adventures -- and nostalgia it is. The mid-80s were suffused with an obsession about Japan and Japanese culture and I got caught up in it like everyone else. Compared to Ninjas and Samurai, boring old Thieves and Cavaliers didn't stand a chance and I was keen to find new ways to play D&D, ways that paid greater heed to history and culture. Or so I thought. In retrospect, I find OA, like most of the products of the Silver Age, well meaning but ultimately wrong-headed and I doubt I will ever again muster much enthusiasm for the kind of earnest, almost evangelical, approach the game took to its real world source material.
I much prefer my fantasy these days to be an unholy goulash of elements borrowed from dozens of sources, Western or otherwise, than fret about "realism" or properly portraying this or that culture in the game. Nowadays, the game takes precedence over any other considerations and source material exists only to inspire me, not to push me toward do anything the "right" way. Granted, this isn't a fault with Oriental Adventures itself, but it's very much a product of a gaming culture that conflated immersion with roleplaying and thus promoted the accumulation of reams of social and cultural details as necessities for "properly" roleplaying. It's not an approach I've favored in some time and I don't miss it at all. These days, if I wanted to include anything deriving from Asia in my fantasy campaigns, I'd present it a lot less reverently than Oriental Adventures did, preferring something more in line with a pulpy "mysterious East" than anything in the real world -- just as I do with anything I borrow from Western history or folklore.