user8708: I understand the idea behind 'bid walls', but on Kraken, prices are being kept low through the use of 'sell walls'.  The volume on this exchange is too low to have a chance of getting through these walls, even when prices on other exchanges are skyrocketing. Every so often, when the price falls a bit, up comes a new 'buy wall' keeping it there. The price on Kraken falls when other markets fall, but gets stopped at the wall on the way back up.  I am curious to know what the strategy behind this tactic could be.


Added 21 Nov for elucidation
On this small volume exchange, a 30 BTC ask equals 10% of the 24hr. volume.  It is the equivalent of a 4500 BTC ask on Bitstamp.  It alters the way bidders approach the market.  When you see such a wall sitting just above the current price, you can be sure the price will not be rising beyond it for at least the next few hours. 
I watched this person re-position this block four times over the course of the day.  Each time, lowering it to sit just above the current bid price.  It was altering the dynamics of this small volume exchange.
I am not asking for you to read anyone’s mind.  I was baffled by this behavior.  I had not seen this strategy before.  I thought that there must be some method to this madness, but I could not see what I might be.  I thought that somewhere in the collective experiences of Stack Exchange there might be someone who was familiar with this strategy and might be able to provide some insight, not necessarily on this person’s behavior, but on the theory behind the strategy being employed.  Assuming, of course, that there is one.

user61391: http://www.dancingbots.com [1] is visualizing the chronological sequence of limit orders on popular exchanges. You can see how those walls are repositioned if the price moves.
Those big positions are an exception. More often those walls consists out of multiple positions spread over a price range. They show up as parallel horizontal lines. If you look at a the usual orderbook graph those spread out positions give an impression of an authentic orderbook imbalance.
Another variation are lots of smaller positions which are canceled after a few seconds reopened gain at a similar price level. I guess they also try to give the impression of a oderbook imbalance, but at the same time try to pretend that the slope is getting steeper. Maybe they try to trigger buy decisions of other bots.
[1] I am the creator of dancingbots.com.

user59297: I use this type of trading to accumulate buys at a cheaper price. Ex: if I spend 2 hours buying small amounts of coins so nobody notices the large buys, then I put up a large sell wall ($30k-$45k) to encourage sells. After that pushes down the market from panic sellers trying to under sell my wall, I instantly buy those sells up and remove my wall and then put in a buy order for enough tokens to raise it 3%-7%. That gets traders attention and I let them take the rest over and pump the price 10%-15% more. Then I drop my accumulated coins on them. Usually, I buy up the orders down to my original 3%-7% I purchased to build the trade tension and that gets written off as me just paying trading fees and the rest of the coins are all profit. This is 1 reason you may see some decent sell walls on random coins that are used just to push the price down. 

user5406: A large investor might be trying to move the market.
Sell walls create an impression of a strong supply. This makes some people, unwilling to wait for the wall to break down, pitch their sales offers below the wall. By moving the wall closer to the current bid again, a large investor might be able to move the market to a small extent and then buy at a lower price. The investor's goal is to move the market, not to actually sell his supply at that price, so when the price gets too close, such walls often disappear or move to a higher price. Especially, if you see the same amount popping up at different prices, there is probably someone trying to move the market without actually fulfilling orders or bids.
Another type of sell wall is composed of many combined sales offers at certain landmark prices, e.g. $600. These usually don't move around.

8708: <p>I understand the idea behind 'bid walls', but on <a href="https://www.kraken.com/market" rel="noreferrer" title="Kraken">Kraken</a>, prices are being kept low through the use of 'sell walls'.  The volume on this exchange is too low to have a chance of getting through these walls, even when prices on other exchanges are skyrocketing. Every so often, when the price falls a bit, up comes a new 'buy wall' keeping it there. The price on Kraken falls when other markets fall, but gets stopped at the wall on the way back up.  I am curious to know what the strategy behind this tactic could be.</p>

<p><img src="https://i.stack.imgur.com/AIuPe.jpg" alt="enter image description here">
<img src="https://i.stack.imgur.com/LVTDY.jpg" alt="enter image description here"></p>

<p><em>Added 21 Nov for elucidation</em></p>

<p>On this small volume exchange, a 30 BTC ask equals 10% of the 24hr. volume.  It is the equivalent of a 4500 BTC ask on Bitstamp.  It alters the way bidders approach the market.  When you see such a wall sitting just above the current price, you can be sure the price will not be rising beyond it for at least the next few hours. </p>

<p>I watched this person re-position this block four times over the course of the day.  Each time, lowering it to sit just above the current bid price.  It was altering the dynamics of this small volume exchange.</p>

<p>I am not asking for you to read anyone’s mind.  I was baffled by this behavior.  I had not seen this strategy before.  I thought that there must be some method to this madness, but I could not see what I might be.  I thought that somewhere in the collective experiences of Stack Exchange there might be someone who was familiar with this strategy and might be able to provide some insight, not necessarily on this person’s behavior, but on the theory behind the strategy being employed.  Assuming, of course, that there is one.</p>
 61391: <p><a href="http://www.dancingbots.com" rel="nofollow noreferrer">http://www.dancingbots.com</a> [1] is visualizing the chronological sequence of limit orders on popular exchanges. You can see how those walls are repositioned if the price moves.</p>

<p>Those big positions are an exception. More often those walls consists out of multiple positions spread over a price range. They show up as parallel horizontal lines. If you look at a the usual orderbook graph those spread out positions give an impression of an authentic orderbook imbalance.</p>

<p>Another variation are lots of smaller positions which are canceled after a few seconds reopened gain at a similar price level. I guess they also try to give the impression of a oderbook imbalance, but at the same time try to pretend that the slope is getting steeper. Maybe they try to trigger buy decisions of other bots.</p>

<p>[1] I am the creator of dancingbots.com.</p>
 59297: <p>I use this type of trading to accumulate buys at a cheaper price. Ex: if I spend 2 hours buying small amounts of coins so nobody notices the large buys, then I put up a large sell wall ($30k-$45k) to encourage sells. After that pushes down the market from panic sellers trying to under sell my wall, I instantly buy those sells up and remove my wall and then put in a buy order for enough tokens to raise it 3%-7%. That gets traders attention and I let them take the rest over and pump the price 10%-15% more. Then I drop my accumulated coins on them. Usually, I buy up the orders down to my original 3%-7% I purchased to build the trade tension and that gets written off as me just paying trading fees and the rest of the coins are all profit. This is 1 reason you may see some decent sell walls on random coins that are used just to push the price down. </p>
 5406: <p>A large investor might be trying to move the market.</p>

<p>Sell walls create an impression of a strong supply. This makes some people, unwilling to wait for the wall to break down, pitch their sales offers below the wall. By moving the wall closer to the current bid again, a large investor might be able to move the market to a small extent and then buy at a lower price. The investor's goal is to move the market, not to actually sell his supply at that price, so when the price gets too close, such walls often disappear or move to a higher price. Especially, if you see the same amount popping up at different prices, there is probably someone trying to move the market without actually fulfilling orders or bids.</p>

<p>Another type of sell wall is composed of many combined sales offers at certain landmark prices, e.g. $600. These usually don't move around.</p>
