Nupur: Is it true the horse for Ashwamedh yaj has to be pure white but with one black ear?
Swami Ram Swarup: Ashwamedh Yaj is the Yaj which is beneficial/glorious for the nation. The meaning of Ashwa is not horse but the Nation. So, in the said Yaj horse is not required.

Dadi Amma: How to improve one’s memory and concentration?
Swami Ram Swarup:The main way/means to improve memory and concentration is to maintain Brahmcharya. In this connection, Patanjali Rishi in his Yog shastra 2/38 states

BRAHAMCHARYAPRATISHTHAYAAM VEERYALABHAHA

Vyas Muni while explaining the sutra states that when the aspirant maintains Brahmcharya, he achieves the benefit of mental and physical power as a result, he attains the best memory. You see, in the ancient times, such students used to remember entire Vedas by heart because at that time, there was no book or printed material but Vedas were taught orally. In this connection, I also paste my answer-

HOW TO ACHIEVE CONCENTRATION

Your question is a question relevant for all aspirants of the world. In Bhagwad Geeta chapter 6, it is stated-

When Yogeshwar Sri Krishna Maharaj asks Arjun to concentrate himself in God by stopping all his chitta vrittis i.e., (faculty which receives knowledge from five senses and passes the same to intellect, is called Chitta and Chitta stores the effect of various karmas to be faced by soul in future at a proper time) which are always attached with worldly materialistic articles, affairs, happening and illusion etc., then in turn Arjun replies vide Bhagwad Geeta shloka 6/34 that Oh! Krishna, the mind (mann) is unstable/fickle/unsteady and always remains indulged in thinking about unlimited matters of the world. It is very strong. Therefore, it is very difficult to control the mind like it is extremely difficult to control air in space. When Krishna heard the answer, in reply, adorable Krishna maharaj said that Oh! Arjun, no doubt, mann is unsteady/fickle and it is very difficult to control but there are two eternal and steadfast ways to control it. One is (Abhyas) practice and second is asceticism (Vairagya). So one must do practice of name jaap, yajyen, make contact with learned sant to learn the same. No doubt, it is very difficult to do the said practice but according to Vedas, shastras and other holy granths, it is also an eternal truth that it is quite impossible that without said practice no one can control the mann. In this connection, Guru bani also states-
“Jup Tup Sanjam Niyam Na Kamaya,
Sadh Sangat Na Jana Hari Raya,
Kaho Nanak Hum Neech Karma
Sharnna Pade ki Rakho Sarma.”
You can again send your question if more details are required or of the concepts are not clear, please.

Anonymous: Is it true that couples can get a son if they plan for Poornmasi day?
Swami Ram Swarup: No, please. It is not true that parents would sure get a son.