It depends how you classify low volume. I can see two big bars on the Bitfinex 24 hour chart, and each of them is above 1000 Bitcoins and mostly buying.
Is buying possible without selling?
No but if the ask side gets eaten into it's considered buying and selling if the bid side gets eaten into.
Ah, gotcha. How does one tell if the ask side got eaten into by looking at the volume bars?
It's hard to say. Generally you would assume that green bar means buying and red bar means selling but it's not always that simple.
Let's say the price is 664.5 and the ask side is just 1 btc to get to 665 so somebody buys 1 btc and the price is now 665 then say somebody puts up a bid wall at 664.8 for 100 btc and 90 of those goes through.
So now the price is 664.8 and 1 btc has been bought and 90 has been sold but the chart still shows that 91 btc has been bought.
I don't pay attention to volume a lot though so somebody else could perhaps clarify it further.
I don't know exactly either, because it seems that you need to look at a combination of behaviors on an ongoing basis, and the order book can be helpful too (rather than merely looking at bars), but the order book can also be a bit of a reverse indicator (even though it still kind of gives you a sense of how many coins it will take to move the price by a certain amount (absent additional market orders that may complicate such conclusions)).
You can attempt to analyze one exchange at a time or you can look at multiple exchanges in order to attempt to get some better ideas because sometime one exchange will follow the other and you cannot be sure whether the parties know each other on the various exchanges or are merely leading, following and/or signaling trade direction. Also, it is not always easy to determine which exchanges are leading and people come to differing conclusions regarding which exchanges are leading and when.. and sometimes, on one pump or dump there will clearly seem to be one exchange that started it, but it is not necessarily the same exchange leading every time.
Further, when the trade volume is low for a long period of time, then the price could remain in a small price range or could be slowly inching in one way or another, so in that regards, you may look at increases in volume to see if there is considerable buying or selling at the time that the prices move begin to move. So if there is low volume, but then all of a sudden, you see 1,000, 2,000 or more BTC sold (or dumped) in a matter of minutes, then you would logically conclude that there is a lot of selling pressure at that particular moment. There could be a lot of fiat ready and waiting at that price and then the big dump would not cause a lot of price movement, but then fiat could be added ad hoc to cause a lot of resistance, and therefore, there is a bit of a gamble whether selling a bunch of coins, all at once is going to cause the price to move and sometimes breaking through resistance points can cause quick 5 or 10% downward price changes... and it is fairly obvious to see how that can be advantages for someone who wants to buy coins cheaper.
Sure, in the end, every buy requires a sell and vice versa, but sometimes you are going to see more movement (slippage) in the price than other times, and when there is a lot of movement downwards we will determine that more coins are up for sale than are being bought and vice versa.
I think that one of the latest series of theories over the past few months is that pushes for BTC prices to go down have been coming with a lot more volume and efforts rather than pushes for BTC prices to go up, so in that regard, buying pressure is greater than selling pressure... and that is reflected also in the upwards price movement overall during the period and difficulties bringing the price below certain price points $600, $550, $500 for example.
Nonetheless, even though there seems to be a bit of a pattern of higher volume attempts to push the price down and lower volume upwards price trickling, it remains unclear whether (or the extent to which) we are being manipulated by whales or if what we can identify is an actual BTC market dynamics in which the bears are having troubles keeping BTC prices down and attempting to get the price to go down.
Bearwhales dump a bunch of coins but those dumps are not very effective because the price trickles back up and does not stay down for any kind of meaningful time.. therefore overall more buying than selling (even though theoretically every buyer requires a seller).
Sure, something else could be going on, and therefore, we continue to watch to attempt to read the BTC price markets and to attempt to make the most accurate guestimates regarding what is going on and the direction in which we expect BTC prices to go in the short-term and the longer-term and sometimes we may get the reading considerably wrong because we think that we see a certain dynamic going on then the BTC prices get manipulated in one direction or another beyond our earlier expectations because sometimes there are bigger players that could be hiding some of their cards (whether it is cash/bitcoins or the spreading of FUCD).
