Exchange started calculation of Order to Trade Ratio (OTR) and related operations after the launch of current J-GATE to enforce efficient ordering practices for trading participants which send a significantly large number of orders, and therefore conserve the exchange's system capacity.
For details, please refer to the URL below: 
[Order to Trade Ratio (OTR)]
https://www.jpx.co.jp/english/derivatives/rules/others/02.html