Tiered link building uses two levels of backlinks to boost your site’s...

https://yenkee-wiki.win/index.php/Will_Too_Many_Low-Quality_Backlinks_Hurt_My_Site_on_Google%3F

Tiered link building uses two levels of backlinks to boost your site’s authority. Tier 1 links point directly to your site and have the most impact. Tier 2 links support those Tier 1 links, making them stronger and safer