As Inca Pachacutec was kept busy by his improvements in Cusco, he no longer had time to go on his forays. Due to this, and as his own children were still too small to carry out royal duties, he entrusted his own brother, Capac Yupanqui, with an expedition to the coast, to visit the prosperous kingdom of Chincha.

This first meeting with the "Chinchans" is strongly marked by the attempt to establish a friendly relationship with them, rather than overcome them by conquest. When he arrived at Chincha, Capac Yupanqui declared his intention was no other than that of obtaining their acceptance of the authority of Cusco, and showed the magnificence of the Inca by showering their curacas with costly gifts. The coastal tribes were happy to recognize the Inca's authority as the price to continue with their peaceful way of life.
The coastal tribes' prosperity derived from their trade using ocean-based rafts with the northern coast towns in present-day Ecuador. What is more, these "indian-style merchants" kept up a thriving land-based trade route with flocks of camelids (alpaca, guanaco, vicuña) to the cities of Collao and Cusco.

Only later on, during the reign of Tupac Yupanqui, would these territories be properly annexed.

The second excursion by General Capac Yupanqui

Some time after the coastal expedition, the Inca gathered his armies for General Capac Yupanqui to lead an expedition of conquest along the road of the Chinchaysuyo, in other words, towards the heights of the sierra.
Near Huamanga, the natives of Parcos resisted in the fortress of Urco Cóllac. Among Capac Yupanqui's troops there was a Chanca chief called Anco Ayllo, who was commander of a contingent of Chancas. Under his orders, they led an assault on the rebel fortress with great bravery, capturing it.

This piece of news infuriated Pachacutec, because he considered that a Chanca victory reflected poorly on the Cusco Orejones (big-ears), so he sent a message to Capac Yupanqui with an order to exterminate all the Chancas. However, a report of this reached the ears of the General's concubine, who was a sister to Anco Ayllo. The woman advised him of the intention of the Cusco soldiers, so the Chanca chief decided to flee with his troops to an area in the jungle where they would be safe from pursuit.

At that time, the Chancas were on the sierra of Huánuco, so they silently left at nighttime with their blongings for the warm lands of Rupa Rupa. When the Inca general discovered their desertion, he pursued them without success. After that, Capac Yupanqui continued his forced march along the sierra to the locality of Cajamarca, disobeying Pachacutec's instructions.
This spot was governed by Gusmango Capac, who for this occasion made an alliance with the Chimú, and awaited the arrival of the Inca armies together with them. Despite their vast number, Capac Yupanqui was victorious and obtained a fabulous booty that amazed the Cusco troops and was laid out on the plaza of Cajamarca. It seems that the general boasted that he had obtained greater treasures than his brother, the Inca. Only then did Capac Yupanqui take the return road to Cusco with his spoils. When he was at Limatambo, messengers arrived from the Inca, ordering the general's capture and sentencing him to death for refusing to destroy the Chancas. According to the Inca tradition, Capac Yupanqui's victory gave him the skill and prestige necessary to lead a successful uprising against the sovereign.