Enhancing the Two-Person Rule: What Teams Can Learn from Shisa Kanko


In DevOps, the two-person rule is a widely adopted practice for ensuring accuracy and safety in critical operations. However, Software engineering teams arent the only ones applying similar techniques - what if we could take this inspiration to further improve the two-person rule? Enter Shisa Kanko, a Japanese technique that’s been used to enhance protocols in all parts of Japanese life.


Shisa Kanko, meaning "pointing and calling," is a safety method extensively used in Japanese railways. Workers physically point at important instruments or controls while verbalizing their observations. This simple yet powerful technique can be adapted to strengthen the two-person rule in DevOps environments.

In aviation, this verbal confirmation is a crucial part of the Crew Resource Management (CRM) normal mode of operating. Pilots call out each step of their pre-flight, in-flight, and landing checklists, ensuring nothing is missed and both pilots are aware of the aircraft's status at all times. This method has proven highly effective in reducing errors and improving safety in one of the world's safest modes of transportation.

How Shisa Kanko can enhance the two-person rule:

  1. Increased engagement: While the two-person rule ensures oversight of critical operations, incorporating Shisa Kanko principles encourages both team members to verbally engage with each other and the task. Both the initiator and the verifier point and verbalize, doubling the chances of catching potential issues.
  2. Multi-sensory confirmation: By adding visual and verbal components to the verification process, teams engage multiple senses, reinforcing the effectiveness of the two-person check.
  3. Clearer communication: Verbalizing actions reduces ambiguity between the two team members, ensuring both are precisely aligned on what's being done.
  4. Enhanced focus: The act of pointing and speaking helps maintain focus during routine checks, combating complacency that might set in with familiar two-person processes.
  5. Documented process: The verbalization aspect of Shisa Kanko can be easily incorporated into logs or recordings, providing clearer audit trails of two-person verifications.

Practical implementation in DevOps could involve:

  • Both team members pointing at and reading aloud critical values before executing major database changes
  • The code author and reviewer both verbally walking through and indicating important sections during code reviews
  • Incident response teams using point-and-call techniques when following checklists or executing critical commands

By integrating Shisa Kanko principles into the existing two-person rule, DevOps teams can create a more robust, engaging, and error-resistant verification process. This synthesis of practices demonstrates how cross-cultural learning can enhance even our most established safety norms, leading to improved operational safety and accuracy.