The article by Oostenveld and Praamstra (2001) introduces a new electrode placement system designed for high-resolution EEG and ERP measurements. The system, referred to as the 5% electrode system or 10-5 system, extends the standard International 10-20 system to accommodate up to 345 electrode locations. This extension aims to promote standardization in high-resolution EEG studies, similar to the transition from the 10-20 to the 10-10 system in 1985. The 10-5 system uses proportional distances of 5% of the total length along contours between skull landmarks, allowing for more precise electrode placement and better comparison between studies. The authors describe the method for determining electrode locations, including the nomenclature for additional positions, and highlight the importance of accurate electrode placement for source analysis and meta-analysis. They also discuss the limitations of the 10-5 system, such as individual anatomical differences, and emphasize the need for unambiguous rules for electrode placement. The proposed system is intended to facilitate high-density EEG applications and improve the reproducibility of electrode placements.The article by Oostenveld and Praamstra (2001) introduces a new electrode placement system designed for high-resolution EEG and ERP measurements. The system, referred to as the 5% electrode system or 10-5 system, extends the standard International 10-20 system to accommodate up to 345 electrode locations. This extension aims to promote standardization in high-resolution EEG studies, similar to the transition from the 10-20 to the 10-10 system in 1985. The 10-5 system uses proportional distances of 5% of the total length along contours between skull landmarks, allowing for more precise electrode placement and better comparison between studies. The authors describe the method for determining electrode locations, including the nomenclature for additional positions, and highlight the importance of accurate electrode placement for source analysis and meta-analysis. They also discuss the limitations of the 10-5 system, such as individual anatomical differences, and emphasize the need for unambiguous rules for electrode placement. The proposed system is intended to facilitate high-density EEG applications and improve the reproducibility of electrode placements.