一字之师是一位传说中的高人，他的传说出现在《庄子·外篇·大宗师》一章中。

传说中，有一天，孔子前去拜访大宗师，问他：“我听说你是一位卓越的文学家，你是否能教我一些写作的技巧呢？”大宗师微笑着回答：“我只能教你一个字。”孔子有些惊讶，但他仍然恭敬地跟着大宗师学习。

几天后，孔子又问道：“我学了这一个字，还有别的吗？”大宗师回答：“没有了。”

孔子离开大宗师的时候，他感到有些失落。但是他很快明白了大宗师的用意。他开始反复思考那一个字，用尽了所有的想象力，深入探究每一个字的含义和用法。在这个过程中，他逐渐领悟到了写作的真谛。

这个故事告诉我们，一个字之师可以引导我们走向正确的方向，让我们深入思考每一个字的内涵和外延，从而更好地掌握写作的技巧。

The Master of One Word is a legendary figure in Chinese culture, and his story appears in the chapter 'The Great and Most Honored Teacher' in the book 'Zhuangzi'.

According to the legend, one day Confucius went to visit the Great and Most Honored Teacher, and asked him: 'I heard that you are an outstanding writer. Can you teach me some writing techniques?' The Great and Most Honored Teacher smiled and replied: 'I can only teach you one word.' Confucius was surprised, but he still followed the Great and Most Honored Teacher to learn.

A few days later, Confucius asked again, 'I learned this one word, is there anything else?' The Great and Most Honored Teacher replied, 'No.'

When Confucius left the Great and Most Honored Teacher, he felt a little disappointed. But he soon understood the intention of the Great and Most Honored Teacher. He began to think repeatedly about that one word, using all his imagination and exploring the meaning and usage of every word. In this process, he gradually understood the essence of writing.

This story tells us that a master of one word can guide us in the right direction, making us think deeply about the connotation and extension of each word, and thus better mastering the techniques of writing.