You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Freemasonry

Context:
Regularity is a concept based on adherence to Masonic Landmarks, the basic membership requirements, tenets and rituals of the craft. Each Grand Lodge sets its own definition of what these landmarks are, and thus what is Regular and what is Irregular (and the definitions do not necessarily agree between Grand Lodges). Essentially, every Grand Lodge will hold that its landmarks (its requirements, tenets and rituals) are Regular, and judge other Grand Lodges based on those. If the differences are significant, one Grand Lodge may declare the other "Irregular" and withdraw or withhold recognition.

Question:
What concept is based on adherence to Masonic Landmarks, basic membership requirements, and tenets and rituals of the craft?

Regularity