One should not look for any other way for becoming a Buddha.

"As for these three important things, it is not that Nichiren said it. It was the spirit of the Tathagata Shakyamuni that entered into my body and filled it with a joy far greater than what it deserved. This is the important teaching of the Lotus Sutra called 'one thought is three thousand realms.' The scripture says, 'All existence has such a form ...' What does this mean? Because the 'appearance of suchness,' the first of the Ten Suchnesses, is the most important, the Buddha appeared in the world. The beginning of Nichiren's believing in the Lotus Sutra is like one drop of one atom in the country of Japan. If two people, three people, ten people, and millions and billions of people recite the Lotus Sutra, then it would become the Mt. Sumeru of Subtle Enlightenment or a great ocean of Nirvana. One should not look for any other way for becoming a Buddha." -- Senji Sho (An Essay on the Selection of the Proper Time)