I love the visual representation of candles. However, as a Volume Spread Analysis(VSA) trader , I know that all that matters is the price spread and where the close is in relation to that spread. With the emphasis on the relationship of the open to the close, candles sometimes obscure the close in relation to the range (spread). Plus, the actual best definition of an UP day is a day where the close is higher than the previous close. Not a day where the close is higher than the open. For a DOWN day, the definition is a day where the close is lower than the previous. Rather than a day with a lower close than its open. Candles again can obscure this fact a bit. Of course volume matters, but that is a discussion for another place.
I strongly disagree with some of Nison's statements. With that said, I think the reasons why Japanese Candlestick pattern analysis (I'm not talking about candlestick charts) is popular is because of marketing. However, I said it's popular and I didn't say it was the most popular. I just see too many traditional indicators (CCI, RSI, MACD, Stoch, Moving Averages et cetera) that are much more popular based upon the number of discussions and the chart examples being posted at different forums on the internet... Easier to discuss. Regardless, most using candlestick patterns are using them incorrectly and there are a few well documented threads here at ET in the past that clearly show misconceptions, inaccurate interpretations, inaccurate application et cetera. Thus, I think the love affair with Japanese Candlesticks is easily lost in comparison to traders having the same problems with traditional western analysis. Think about it, if CCI isn't working well...traders will change a setting or tweak it. However, few have the same tolerance when they have problems with Japanese Candlestick analysis. Further, most traders using candlestick charts aren't even doing any Japanese Candlestick Analysis. Simply, bar charts has the same price action as candlestick charts. My primary methodology doesn't involve candlestick patterns but I do prefer candlestick charts instead of bar charts or any other types of charts. Candlestick charts just look nicer...it's a preference. Also, there are a few reliable patterns. Mark (a.k.a. NihabaAshi) Japanese Candlestick term
It may, or may not, interest you to know that while candlesticks are still used on almost all printed charts here in Japan, very few people use the candlestick patterns as a form of analysis.