During all these years it is to Sil-la that we must look for any signs of internal improvement, any of those innovations which are the mile-stones of progress. We saw above how she introduced the use of the cart and so raised a great burden from the shoulders of the people. The wheel is the great burden bearer of history. And now we find her introducing further reforms. The first was the horse relay system called the _yong-ma_. It did not bear so directly upon the condition of the people but it afforded an opportunity for the rapid transmission of official information and thus indirectly had an important bearing upon the welfare of the masses. In the next place, she organised a general market where at stated intervals merchants from the various districts could meet and exchange commodities. These are things that we look upon as matters of course and we do not realise their importance till we imagine ourselves deprived of the comforts that spring from the possibility of rapid communication and exchange of commodities. That Ko-gu-ryŭ had not made similar advances in the line of industrial reform is shown by the fact that when the Emperor of the Wei dynasty sent to grant investiture to Na-un the twenty-first king of Ko-gu-ryŭ in 499 he presented him with suits of clothes, flags, a crown and a cart. This shows that carts were not as yet in common use in Ko-gu-ryŭ. As for Păk-je, disaster was following upon disaster. At one time a thousand people were swept away in a flood. Then famine carried away three thousand. A few years later ten thousand people passed over into Sil-la to save themselves from starvation.
The sixth century dawned upon a comparatively peaceful Korea; for the time being the dogs of war were held in leash and feuds seem to have been laid on the shelf. The three kingdoms employed their time in different but characteristic ways. The king of Păk-je built an enormous pleasure-house and adorned it with all manner of curious flowers and animals. To the expostulations of his ministers he turned a deaf ear. A few years later he was murdered by one of his courtiers. In truth, peace was nearly as bad for Păk-je as war.
In Sil-la Buddhism had been introduced during the reign of Nul-ji, 417-458. A monk named Muk Ho-ja had been well received and was lodged in the palace. But, at the first, Buddhism did not find congenial soil in Sil-la. Tradition gives the following account of the first set-back which it suffered there. In 502 while the king was idling an hour away in a favorite summer-house outside the city, a raven appeared bearing in its beak a letter. It laid the missive at the king’s feet and flew away. The superscription said “If the king opens and reads this note two people will die; if he does not open it one will die”. He determined not to open it, but one of his attendants said, “The one referred to is Your Majesty and therefore you should open it even though two lives are sacrificed”. He broke the seal and read the strange words “Let the king take his trustiest bow, hasten to the palace and shoot an arrow through the zither case”. The king obeyed the mandate, hastened back to the palace by a private gate, entered the queen’s apartments unannounced and shot an arrow through a zither case that stood against the wall. The arrow pierced the zither case and the High Priest who was hidden behind it. The latter had taken advantage of the king’s absence to attack his honor. He was strangled together with the guilty queen.