A method of matching orders that involves using an auction-like process to trade securities. The orders are organized by both their prices and the time that they were taken. As soon as an order for a security is delivered, it is compared and matched with orders already in the order book. When a bid comes in that matches the price requested by another order, the two orders are executed and taken out of the order book.




Taobiz explains Zaraba method
The zaraba method is most often associated with the Japanese stock exchanges. Typically, the zaraba method is used during normal trading sessions, whereas a different order matching method, which is called the itayose method, is used to determine the opening and closing prices for each morning and afternoon trading session.