Equivolume is a candlestick chart that combines volume and price data. Devised by Richard Arms Jr, the equivolume chart differs from Japanese candlesticks in including data about volume of trade to price data, as opposed to just price data in Japanese candlesticks. The inclusion of volume data means that candlesticks are not only seen in terms of height or length of the body/shadow, but also in terms of width of the candlestick. So candlesticks with wider bodies indicate larger volumes, and thinner candlesticks indicate lower trade volumes.
In an equivolume chart, the candlesticks are known as equivolume boxes. Each equivolume box depicts the price high, price low and the volume. The essence of adding data about trade volume is to validate support/resistance breaks as well as reversals. A move of an asset with high volume indicates that more traders are acting in that direction, thus serving as a validation of any breakouts or reversals.