The period between the sandhyās and the beginning and end of the yuga which are calculated in hundreds of devatā years is called the yuga by the wise. During this period the particular dharmas of the yuga are performed. The juncture at the beginning is called sandhyā and the juncture at the end is called sandhyāṁśa. What are these? They are counted in hundreds of years. The period between these two is the yuga. In these yugas the special dharmas of meditation, sacrifice, deity worship and chanting are performed. The regular dharmas are secondarily performed. These are practiced as well in the sandhyā and sandhāṁśa. But even in the sandhyās, the yuga dharmas are more prominent. One year of the devatās is 360 years of humans. The four yugas are described in the scriptures to be 4, 320,000 human years. Satya-yuga is 1,728,000 human years. Treta-yuga is 1,296,000 human years. Dvāpara yuga is 864,000 human years. Kali-yuga is 432,000 human years.