---
title: "Discussion on \"Handling Known and Unknown Unknowns with Testing and Observability\" | Hashnode"
description: "Discussion on \"Handling Known and Unknown Unknowns with Testing and Observability\". In modern software development, we often face three types of risks:\n\nKnown knowns: issues we are aware of and understand.\n\nKnown unknowns: issues we know exist but lack full understanding.\n\nUnknown unknowns: issues we neither know exist nor understan..."
url: "https://hashnode.com/posts/handling-known-and-unknown-unknowns-with-testing-and-observability/680f5351b4759ca7745f4937"
---

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# [Handling Known and Unknown Unknowns with Testing and Observability](https://blog.yasaichi.com/handling-known-and-unknown-unknowns-with-testing-and-observability?utm_source=hashnode&utm_medium=feed)

In modern software development, we often face three types of risks: Known knowns: issues we are aware of and understand. Known unknowns: issues we know exist but lack full understanding. Unknown unknowns: issues we neither know exist nor understan...

Apr 28, 2025 · 3 min read · blog.yasaichi.com  
Updated Nov 9, 2025  
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-   [#rumsfeld-matrix](https://hashnode.com/tag/rumsfeld-matrix)
-   [#testing](https://hashnode.com/tag/testing)
-   [#property-based-testing](https://hashnode.com/tag/property-based-testing)
-   [#logging](https://hashnode.com/tag/logging)
-   [#observability](https://hashnode.com/tag/observability)
-   [#sre](https://hashnode.com/tag/sre)

## Written by

[Yuichi Sato](https://hashnode.com/@yasaichi)

@yasaichi · Tokyo, Japan

  
[View profile](https://hashnode.com/@yasaichi)

Software Engineer at a Tokyo-based company

Typescript/Effect enthusiast, Functional Programming pragmatist, Co-author of “Perfect Ruby on Rails“, ex-CTO at a public company.

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