The question here is what would people have been smoking in Central and Eastern Asia in the 700's AD? I've got information about the derivation of my question from a movie, but the question is NOT about the movie. The movie is fictional entertainment, so full of inaccuracies, but raised the question in my mind.
I was recently watching a film on Netflix, "Warriors of Heaven and Earth" (2003) which, while it wasn't a documentary at all, was set in the North-Western region of China, I think in the Xinjiang and Quinghai provinces, on the borders with Tibet and India and around the Gobi Desert.
According to Wikipedia the film is set in approximately 700 AD, and features a group of warriors escorting and protecting a sacred Buddhist relic while it is being taken to a capitol city and the temples there. The relic is wanted by a Goturkic khanate and is under constant threat.
At one point in the film, the group are attacked by a band of the Goturkic warriors and head into the desert to escape detection. However, they are followed by the Goturks and one of the protagonists mentions (as translated from Chinese in the subtitles of the film)
They have been following us for two days...
I can smell their tobacco in the air.
The second line being a boast of his abilities as a soldier.
This boast got me thinking - there certainly wasn't tobacco (Nicotiana tabacum) present in China in the 700's (introduced to the old world in the 1500's; the word "tobacco" is derived from the Carib name, though possibly from Arabic), so if people were smoking something, it wouldn't be that. I would guess that the Goturkic cultures had access via the Silk Road to the resources of the Middle-East and certainly parts of India and surrounding regions. This might mean access to Persian Tobacco (Nicotiana alata), which is used as a tobacco currently, but smoking only dates to around 1500 in the Middle East, and seems to have been introduced from China/Asia, so there's some evidence that smoking existed prior to the 1500's (soft paywall) - if it was common enough in Asia to be introduced elsewhere, it was probably fairly common. They definitely had access to Cannabis, which is native to the area in question, and there's even evidence that it was selectively grown for it's psychoactive properties (probable paywall), in the Pamir region (Tajikistan/NW Himalaya) for use in rituals, and was used for several thousand years before recorded history. In addition, there was also Opium (comments tell me that this was a later introduction). However, the sedative effects of both Cannabis and Opium would be unlikely for soldiers on a mission, I would have thought.
I've done some google searches and looked through PubMed (I'm a virologist, not a historian), but I can't find much on this topic. Quite a lot seems to have been done on American cultures and Western Europe, even the Middle-east, but not Asia.
So, the question is - what could they have been smoking at the time, and what is known about smoking in Asia over history? I'd be especially happy with answers centred on Eastern Asia, but Southern China and Mongolia/Kazakhstan/Kyrgyzstan/Tajikistan area and Bhutan/Nepal areas would also be interesting.
Related question on this SE for Europe/Britain.
For those interested the timestamp on the movie is 1:21:27. I don't have any Chinese, but I can't hear anything resembling "tobacco" or the Mandarin Hanyu Pinyin "Yāncăo" in there.