Perform the asset register easily

Answer:
It is the most easy way, I mean, matching threats and vulnerabilities for each asset although if you want to reduce the work, the best recommendation is to reduce the number of assets, for example grouping similar assets with the same threats/vulnerabilities. For example: laptops (for all laptops), workstations (for all workstations), printers (for all printers), etc.

Anyway, it is not mandatory to have an asset based risk management, although is very recommendable to work with the asset based risk management, because is more easy that other methods.

This article can be interesting for you “ISO 27001 risk assessment: How to match assets, threats and vulnerabilities” : https://advisera.com/27001academy/knowledgebase/iso-27001-risk-assessment-how-to-match-assets-threats-and-vulnerabilities/

And also our online course, because we give more information about the risk assessment “ISO 27001:2013 Foundations Course” : https://advisera.com/training/iso-27001-foundations-course/