I have never fully understood the relationship between time periods and E-mini trading. After all, time is an arbitrary measurement established by humankind and does not tell me much about price action or potential price movement. I realize that I am in the minority in this view, which is nothing new for me; on the other hand, if you really want to focus on price action why not use bars that are designed to do just that?
Candlesticks are noisy and hard to interpret and I have many e-mini trading students struggle trading the darn things. We tend to set specific time periods to measure price action and make specific decisions based upon the price action that occurs during that time period. This seems counterintuitive to me, as the market does not trade with 3 minute, 5 minute, or 15 minute increments. Price action is an ongoing and evolving variable that changes throughout the course of the day. I am interested in pure price action; and I am not interested in all the noisy machinations that are trading "background noise." When trading candlesticks you get the whole package; price movement and all the accompanying background noise.
Renko and range bars form without benefit of any time constraints; they simply express exactly what the price is doing at a given point of time during the trading day. Renko bars have their origin in Japanese trading and are solely concerned with price action; there is no time constraint on how long it takes a 4 Renko bar to form. It only forms when the market moves 4 ticks in the same direction. 4 Range bars form within price action moves four ticks in any direction. That being said, non-time related bars are especially useful for support and resistance traders as these levels are easily seen because of the nature of Renko bar movement.
There are a number of variations of Renko bars besides the traditional "bricks" used in traditional bar trading. I personally prefer the "Better Renko" bars because they clearly indicate the range of a given bar during its formation. More recently "UniRenko bars" have made their appearance; these bars are similar to Better Renko bars but they use an averaging system that is similar to Heiken-Ashi bars. I have had great success with Heiken-Ashi trading during trending markets but they can be a little tricky in a sideways market. For that reason alone, I stick with the Better Renko bars and have done so for the past six years.
Candlesticks on the other hand have their uses, but you have to contend with a great deal of market noise interpretation and I have found this is the realm of the most experienced traders. I start off my new traders with price action oriented bars with great success.
Have you used Better Renko bars? You might read up on them and identify the advantages and disadvantages they may have over traditional candlestick bars. They're not for everybody, but they are for me.