When you go to the Dojo select unlock bonuses, then you go to unlock Characters tab. All characters in the shop you have to pay for except Yukimura Sanada, Hanzo Hattori, Kenshin Uesugi, Nobunaga Oda, Oichi, Ginchiyo Tachibana, Kanetsugu Naoe, Hanbei Takenaka, Kai, and Kiyomasa kato for they are starting characters so they cost nothing. Some may cost 80 tons of rice while Others cost 100 tons of rice(primarily those with a story mode.) Takamaru needs to be unlocked a different way so check somewhere under Secret Characters section)

Character	How to unlock
Hideyoshi Toyotomi	Pay 100 tons of Rice
Ieyasu Tokugawa	Pay 100 Tons of Rice
Ina	Pay 100 tons of Rice
Kanbei Kuroda	Pay 100 Tons of Rice
Katsuie Shibata	Pay 80 Tons of Rice
Keiji Maeda	Pay 100 tons of Rice
Kotaro Fuma	Pay 80 Tons of Rice
Kunoichi	Pay 100 tons of Rice
Magoichi Saika	Pay 100 tons of Rice
Masamune Date	Pay 100 tons of Rice
Mitsuhide Akechi	pay 100 tons of rice
Mitsunari Ishida	Pay 100 Tons of Rice
Motochika Chosokabe	Pay 100 Tons of Rice
Motonari Mori	Pay 100 Tons of Rice
Muneshige Tachibana	Pay 100 Tons of Rice
Nagamasa Azai	Pay 100 Tons of Rice
Nene	Pay 100 Tons of Rice
Noh	Pay 80 tons of Rice
Okuni	Pay 80 Tons of Rice
Ranmaru Mori	Pay 80 tons of Rice
Sakon Shima	Pay 100 Tons of Rice
Shingen Takeda	Pay 100 Tons of Rice
Tadakatsu honda	Pay 100 Tons of Rice
Toshiie Maeda	Pay 80 Tons of Rice
Ujiyasu Hojo	Pay 100 Tons of Rice
Yoshihiro Shimazu	Pay 100 Tons of Rice
Yoshimoto Imagawa	Pay 80 Tons of Rice