正坐當中 The Sovereign Sat in the Middle
師徒四眾與文武多官，俱侍列左右。太宗皇帝仍正坐當中。歌舞吹彈，整齊嚴肅，遂盡樂一日。正是：师徒四众与文武多官，俱侍列左右。太宗皇帝仍正坐当中。歌舞吹弹，整齐严肃，遂尽乐一日。正是：
逐句解 Line by line
Master and disciples, four of them, with the civil and military officers, all stood ranged in attendance on either side.
⚠ 俱侍列左右 — all attending, ranged left and right. Everybody stands. And the four of them are in the line with the officials, which is the first time the pilgrims and the Tang court appear in one formation.
The Emperor Taizong sat, as before, squarely in the middle.
⚠ 正坐當中 — sat right in the centre. The last character is read dāng: at, in, occupying. Read dàng it means to treat something as, which is a different word. 仍, as before, still. One character, and it puts everything back where it was: everybody else standing, the emperor seated, exactly as in the audience hall. The Tang monk was given a chair upstairs. Here he is standing with the rest.
There was singing and dancing, wind and strings, all orderly and grave, and so they took their fill of pleasure for a whole day.
⚠ 吹彈 — blowing and plucking, which is how Chinese names the two halves of an orchestra. Its second character is read tán here, to pluck a string; the bare reading gives dàn, a pellet or a bullet. ⚠ 整齊嚴肅 — orderly and grave. That is a strange thing to say about singing and dancing, and it is exactly right for a Tang state banquet: the entertainment is protocol. 盡樂一日 — took their pleasure to the full, one whole day. The middle character is lè, joy, not yuè, music, which would be the obvious guess in a sentence about an orchestra.
This is just what is meant:
The seventh and last verse cue of the chapter's first half, and the shortest.
The sovereign's fine assembly outdoes Tang and Yu; the true scriptures got, there is blessing to spare.
⚠ 賽唐虞 — outdoes Yao and Shun. Tang and Yu are the two legendary sage-emperors of high antiquity, the standard by which every later Chinese ruler is measured and found wanting. The verse says Taizong's dinner party beat them. It is flattery of a very Chinese kind, and it is being paid to a man the same poem has just placed in a year of his reign that never existed.
Handed down a thousand ages, flourishing a thousand ages; the Buddha's light shines everywhere on the dwelling of kings.
⚠ 千古流傳千古盛 — the same two characters twice, at the head of each half. Handed down for a thousand ages; flourishing for a thousand ages. ⚠ And the last line is where the two halves of the book meet: 佛光普照帝王居, the Buddha's light shining on the palace of kings. Not on a monastery, not on the Spirit Mountain — on the emperor's house. Every poem in this chapter so far has ended on the court. That is where the scriptures have arrived, and the novel keeps saying so.
Everybody stands and the emperor sits, exactly as in the audience hall — the word is as before. The Tang monk was granted a chair upstairs; down here he is in the line with the officials.
⚠ And the entertainment is described as orderly and grave, which is a very odd thing to say about singing and dancing and an orchestra, and exactly right for a Tang state banquet. The pleasure is protocol. They take their fill of it for a whole day.
⚠ The closing matched pair of lines says the party outdid the sage-emperors of high antiquity, which is the highest compliment Chinese has and is being paid to a man the same page has placed four years past his own death. Then it ends where every poem in this chapter ends: not on the Spirit Mountain, not on a monastery, but on the Buddha's light falling across the palace of kings.