However, Tamushichinki from the Nagoya period remained the most popular product.

Further, the super long-selling Hakkiri ("clear"), which continues to sell to this day, more than 50 years after World War II, was launched in 1939. Hakkiri was the name for the eye drops originally manufactured by an Osaka company named Asano. Kobayashi Daiyakubo acquired this company and discontinued the manufacture of the eye drop, instead transferring the name Hakkiri to its headache medicine.

Hakkiri, which subsequently became Kobayashi Pharmaceutical's mainstay product, was initially manufactured in the headquarters in Kyomachibori, but in November 1940 Kobayashi Pharmaceuticals Co., Ltd. was established, a cutting-edge factory was built in Jyuso (currently the Osaka Plant) and the manufacture of Hakkiri was transferred to this new factory.

Hakkiri did not get off to a completely smooth start. Noshin and Hareyaka were powerful rivals, and in particular Kobayashi was a nationwide agent for Hareyaka. Kobayashi gave up this right, put all of its effort into expanding sales of Hakkiri, and succeeded in securing a foothold for the product.

Kichitaro's business practices prioritized both manufacturing and wholesale stores, as if they were two wheels of a vehicle. However, Kichitaro had decided to push ahead in order to sell products the company had developed itself, even if it meant giving up agency rights as with Hareyaka. In Hakkiri's case, the product
was very marketable, and Kichitaro made the decision in difficult circumstances.

This problem was inevitable as long as Kichitaro prioritized both manufacturing and wholesale stores. When making decisions, the issue had to be examined from many aspects. The trading sector is very important to Kobayashi Pharmaceuticals, and since its founding there have been many examples in which the development and launch of a product was discontinued due to respect for a customer's wishes.

One could not emphasize one side while disregarding another side. Whatever the choice was, this would be the standard for Kobayashi Pharmaceutical's future development. Kichitaro's decision would be justified by the subsequent growth of Hakkiri.

While the manufacturing sector continued to develop a series of new products, as mentioned above, Kobayashi Pharmaceuticals took an aggressive approach in acquiring existing manufacturers, as it did with the Hakkiri eye drop, and merging with others.

On a personal basis, Kichitaro was extremely enthusiastic about development. Kichitaro firmly believed that a full-scale entry into manufacturing and the reinforcement of this sector were indispensable to Kobayashi's future.

The most appealing factor was that profitability was much higher than that in the wholesale sector. However, it required heavy capital investments and the risk was high. Kichitaro also understood that the manufacturing sector could not be expanded overnight.

Kichitaro established the subsidiary, Kobayashi Pharmaceuticals, and built a factory, coming one step closer to his dream. It was Kichitaro's successor that brought this dream to fruition.