六難九易 - The six difficult and nine easy acts.

本文
法華経の 一句一偈の いはれをも 尋ね問う人はありがたし、此の趣を釈し給いて 人の御不審をはらさすべき僧も ありがたかるべし と、法華経の四の巻・宝塔品と申す処に 六難九易と申して 大事の法門 候

妙法尼御前御返事
［一句肝心事］
（１４０２頁）
弘安元年７月
（１２７８年）

通解（意訳）
（末法において）

法華経の一句一偈（一区切り、一部分）の意義を尋ね問う人は稀である。またこの趣旨を説き聞かせて、人の疑問を晴らすことのできる僧侶も稀であると、法華経の第四の巻・宝塔品という箇所に、六難九易（ろく なん く い）といって大事の法門が説かれている。

English Gosho
 In this age of the Latter Day of the Law, those who ask about the meaning of even one phrase or verse of the Lotus Sutra are far fewer than those who can hurl Mount Sumeru to another land like a stone, or those who can kick the major world system away like a ball.
 They are even fewer than those who can embrace and teach countless other sutras, thereby enabling the monks and lay believers who listen to them to obtain the six transcendental powers.
 Equally rare is a priest who can explain the meaning of the Lotus Sutra and resolve people's doubts concerning it.
 The “Treasure Tower” chapter in the fourth volume of the Lotus Sutra sets forth the important principle of the six difficult and nine easy acts.
 Your asking a question about the Lotus Sutra is among the six difficult acts.

 This is a sure indication that, if you embrace the Lotus Sutra, you will become a Buddha in your present form.

" The One Essential Phrase "
"The Writings of Nichiren Daishonin", Vol.1, p. 922
July, 1278.
[ --- ] is liberal translation.

参考文献：
「日蓮大聖人御書全集」
「御書をひもとく」
「英語で学ぶ御書」
第三文明社
Bibliography :
"The Writings of Nichiren Daishonin"
"The Record of The Orally Transmitted Teachings"