This site is dedicated to first Russian tabletop roleplaying games Zakoldovannaya strana (Enchanted Country) and Zaklyatie Chyornogo maga (Black Mage Spell) with their legacy. Both games are using unique way to emulate 18-sided die with uniform probability. That's why I classify them as d18 family systems. In Russian 'die' means 'кость'. So d18 and к18 is the same. Or just k18 for simplicity and originality.
The English version of this site was recently opened as a placeholder for the future translations. But you can definetly try to read original texts with a help of Google Translate.