Thunder and lightning together: a hexagram of fullness at its height, where success comes with the counsel to stay like the noon sun and not overreach.
The lower trigram is Li ☲, fire, bright and clinging; the upper is Zhen ☳, thunder, whose quality is movement. Zhu Xi reads brightness that moves as a force at the height of its power, so there is success. Yet fullness at its peak turns toward decline; rather than worry about that, the text counsels keeping to the steady measure of the midday sun.
Judgment (卦辭)
The text attached to the whole hexagram, read when no line is changing.
豐，亨，王假之。勿憂，宜日中。
Feng: success. The king reaches this. Do not worry. It is fitting to be as the sun at midday.
豐 means great. Brightness that sets things moving has a vast, flourishing force, so there is success. But when a king reaches this point, Zhu Xi says, fullness at its height must turn to decline, and that gives cause for worry. The sages held that worry alone is useless; it is enough to keep to the ordinary measure and not go past the height. Hence: do not worry, and be like the sun at noon. The counsel is steadiness at the peak, not dread of what follows.
Image (大象)
The Image commentary (象傳) reads the whole hexagram from its two trigrams.
雷電皆至，豐。君子以折獄致刑。
Thunder and lightning arrive together: Feng. The noble person, accordingly, settles legal cases and metes out penalties.
Zhu Xi takes from this image the awe of thunder and the light of lightning working together. The noble person's judgments, likewise, call for both clear sight and the force to carry them through.
Lines (爻辭)
From the bottom line to the top. In the line names, nine (九) marks a yang line and six (六) a yin line.
Line 1, yang (初九)changing line in the shared reading
遇其配主，雖旬无咎，往有尚。
Meeting one's matching lord. Though they are equals, no blame. Going forward wins esteem.
The matching lord is the fourth line, and 旬, Zhu Xi says, means equal: both lines are yang. Two yang lines would not usually answer each other, but in a time of abundance, brightness below and movement above depend on one another. So when the first line meets the fourth there is no blame, and going forward is esteemed.
Line 2, yin (六二)changing line in the shared reading
豐其蔀，日中見斗，往得疑疾。有孚發若，吉。
The screen is made thick; at midday the Dipper appears. Going brings suspicion and ill will. If there is sincerity to rouse him, good fortune.
As ruler of the bright lower trigram, the second line is as bright as can be, yet its counterpart, the fifth, is soft and dark. So the screen (蔀) grows thick and stars show at noon, and following such a lord would only bring suspicion. The way through, Zhu Xi says, is to build up sincerity until it moves the other; a line open at the center is itself an image of sincerity.
Line 3, yang (九三)changing line in the shared reading
豐其沛，日中見沬，折其右肱，无咎。
The curtain is made great; at midday the small stars appear. The right arm is broken. No blame.
Zhu Xi notes that one version writes 沛 as 旆, a hanging banner or curtain, which blocks even more than the screen of the second line; 沬 are tiny stars. The third line stands at the peak of brightness but answers the weak top line. Like a broken right arm, it cannot be put to use, yet the fault is not its own.
Line 4, yang (九四)changing line in the shared reading
豐其蔀，日中見斗，遇其夷主，吉。
The screen is made thick; at midday the Dipper appears. Meeting the lord who is one's peer. Good fortune.
The image repeats that of the second line. 夷 means a peer, and here, Zhu Xi says, it refers to the first line. His reading: in a time of abundance under a dim ruler, going down to join someone of the same quality brings good fortune. It is the first line's meeting with its matching lord, seen from the other side.
Line 5, yin (六五)changing line in the shared reading
來章，有慶譽，吉。
Bringing brilliance in, there is blessing and renown. Good fortune.
By nature the fifth line is soft and dark. But if it can draw the brightness of the world to itself, there will be blessing and renown. Zhu Xi says the text sets this out precisely because the line is weak and dim, to open a way for it, and the verdict applies to one who can do this. What one lacks can be supplied by those one welcomes.
Top line, yin (上六)changing line in the shared reading
豐其屋，蔀其家，闚其戶，闃其无人，三歲不覿，凶。
He makes his house great and screens off his household. Peering through the door: silence, no one there. For three years no one is seen. Misfortune.
Weak yin at the height of abundance and the end of movement, the top line is brightness at its limit that turns into darkness. It enlarges its house only to wall itself in. The empty doorway and the three unseen years, Zhu Xi says, both describe how deep the screening has gone, and he judges the misfortune severe.
If you drew this hexagram
Which text to read depends on how many lines are changing. With none, read the judgment; with one, read that line; with more, follow Zhu Xi's rules in the Yixue qimeng.
Text: Zhu Xi, Yuanben Zhouyi benyi (原本周易本義), Siku Quanshu Wenyuange copy, as transcribed by the Kanseki Repository (KR1a0031), corrected and punctuated by K-magpie. Translation and explanation: written by AI (Claude) from Zhu Xi's commentary and checked against the text and commentary. Sources and the list of corrections are on the Today's Hexagram page.
Characters corrected in this hexagram — Line 1, yang (初九): 雖旬尤咎 → 雖旬无咎