In recent years, computers, artificial agents, intelligent robots, and other intelligent systems have become normal parts of our everyday lives, so high interpersonal affinity, including smooth communications and bidirectional interactions with people, have become necessary for the development of intelligent systems.

“Human Symbiotic Systems” (HSS) is an area of research to study the basic principles and methods used in the designing of intelligent interaction systems, or systems with bidirectional communications based on the symbiosis and effective collaboration between people and robots, agents, computers, etc. In HSS research, the establishment of elemental technologies necessary for the realization of intelligent systems to coexist with people is a main target.

The research society “Human Symbiotic Systems” was established in the Japan Society for Fuzzy Theory and Intelligent Informatics in 2007 by the guest editors of this special issue. The HSS aims to encourage academic and industrial discussions on research of Human-Agent Interaction (HAI), Human-Robot Interaction (HRI), Human-Computer Interaction (HCI), etc.

The aim of this special issue is to activate and expand top-quality research in the area of the theory and applications of Human Symbiotic System (HSS). This special issue “Human Symbiotic Systems II” (HSS-II) is the second special feature of the HSS. The first special issue appeared as JACIII journal Vol.14, No.7 in 2010. Various technologies have been developed in the past ten years, but HSS continues to be an important area of study in the field of engineering today.

For this special issue on HSS-II, 10 papers were received, and 7 papers were accepted for publication after two peer reviews each. We would like to thank the authors and referees for their great efforts. Through their contributions, this special issue was made possible and overall paper quality was improved.