Here is David D. Neilson's Shincho-Ko ki Okehazama translation (Society at War pp.56-60).
The End of Imagawa Yoshimoto
Eiroku 3 (=1560), fifth month, seventeenth day.
Imagawa Yoshimoto came to Kutsukake leading his army. On the evening of the eighteenth, Sakuma Daigaku and Oda Genpa reported to Lord Nobunaga in Kiyosu that the Imagawa were probably planning placing men and food in Otaka Castle on the night of the eighteenth. Before [the] reinforcements [that they were requesting from Nobunaga] could arrive at Washizu and Marune Forts in the morning, having taken the ocean tide into consideration, the Imagawa [most likely] intended to attack and take control of the two forts that lay between [Imagawa's] Otaka Castle and [Oda's] Narumi Castle. However, Lord Nobunaga mentioned nothing of his military plans on that night and merely chatted with his generals. He noted that is was late and sent everyone home. The generals laughed at Nobunaga, saying "this is a perfect illustration of the maxim that when a man's luck runs dry, his wisdom becomes clouded" and left. As anticipated, at daybreak [on the nineteenth], messengers arrived with news from Oda Genpa and Sakuma Daigaku that the Imagawa had already begun invading Washizu and Marune Moutains. This is when Nobunaga performed the famous dance scene from [the noh play] Atsumori.
Genten no uchi wo kurabereba
Yumemaboroshi no gotoku nari
Mesenu mono no arubeki ka
Then he ordered that the war conch be blown and that his armor and weapons be brought to him. He put on his armor immediately and ate while standing up. Then he put on his helmet and left for battle. He was accompanied by his pages; Iwamura Nagatonokami; Hasegawa Kyusuke; Sawaki Tohachi (Maeda Toshiie's younger brother); Yamaguchi Hidanokami; and Kato Yazaburo. [The] Master and servants totaled six people and they mounted their horses and rode the [first] three ri (approximately 12 kilometers) at a fast pace. At about eight in the morning when Lord Nobunaga looked to the east from [where he was standing] in front of Kamichikama no Yashiro [Shrine] smoke was visible and it appeared that Washizu and Marune Forts had already fallen. Nobunaga was accompanied by only six mounted men and two hundred zohyo foot-soldiers.
Lord Nobunaga thought that if he went by the way of the beach, it would be shorter, but because the tide was high, it would be particularly difficult for the horses. Therefore, he decided to go by the upper road from Atsuta and rode hard, arriving at Tange Fort. He then went to Zenshoji Temple where Sakuma Daigaku was in charge. There he set up camp and took time to asses the situation and decide on a battle strategy. He discovered that his enemy, Imagawa Yoshimoto, led forty-five thousand soldiers and was currently taking a break to rest his men and horses at Okehazama.
At noon on the nineteenth, Yoshimoto positioned his men to the northwest and captured Washizu and Marune Forts. Yoshimoto performed three [noh] songs and commented that he could not have been more satisfied [with how things had gone so far].
In this battle [Tokugawa] Ieyasu acted as [Imagawa Yoshimoto's] vanguard and made use of his akamusha red corps. He brought provisions with him to Otaka Castle so that his men and horses could rest, [but they still] had difficult time taking Washizu and Marune Forts.
Knowing that Lord Nobunaga had come to Zenshoji Temple, Sassa Hayatonosho and Senshu Shiro led three hundred men against Yoshimoto's men. Fifty-some cavalry including Sassa Hayatonosho and Senshu Shiro died in battle. Yoshimoto was delighted and said 'Even devils or gods cannot stop Yoshimoto! I feel good!' He was singing in camp as well.
Lord Nobunaga considered this and tried to move to Nakashima, but his generals stopped him by grabbing the bit of his horse. The generals said that the path to Nakajima was narrow and bordered on both sides by fields of deep mud and could only be traversed single file. The enemy would be able to see clearly that the force that Nobunaga led was very small and that was a bad idea. Lord Nobunaga shook off his generals and proceeded to Nakajima. His army at that point numbered less than two thousand men. [Finally, the generals were successful in stopping Nobunaga himself from going on, but] Lord Nobunaga sent his army beyond Nakajima. Lord Nobunaga said "Everyone listen! The Imagawa soldiers are exhausted because they haven't eaten last night and had a difficult time taking Washizu and Marune Forts. We are a fresh force. Do not be scared just because the enemy is large and we are small. Heaven decides who shall win and who shall lose. If the enemy attacks, retreat. If the enemy retreats, pursue them and attack. No matter what happens, overpower the enemy and destroy them. It's easy. Do not take heads, just cut them down and move on! If we win this battle, all who take part will bring honor and fame to their families forever! Fight hard!" At that time, [the generals] Maeda Matazaemon (=Toshiie), Mori Kawachi no Kami, Mori Juro, Kinoshita Yoshitoshi, Nakagawa Kinemon, Sakuma Yataro, Mori Kosuke, Ajiki Yataro, and Uozumi Hayato, arrived carrying the heads of some of the enemy. Lord Nobunaga repeated his orders to them.
The army then moved into the mountains. A storm blew in from our rear and suddenly it began to rain down upon the enemy with the power of stones or icicles. At the foot of Kutsukake Pass, large camphor tree was blown down in an easterly direction by the wind coming to rest at the foot of a small pine. Those present asked "Is this was a battle in which Atsuta Damyojin [The tutelary deity of the Oda Clan] is taking part?" Soon the rain slackened. Lord Nobunaga took his spear and raising it over his head yelled "Attack! Attack!" The enemy looked at Nobunaga's army as they [came out of the forest] and began their attack. The Imagawa troops were surprised, unprepared, and disorganized and they retreated, scattering [before Nobunaga's men]. Bows, spears, banners, and swords were scattered everywhere and [the camp] was in great confusion. Yoshimoto's palanquin was abandoned by the men around it and Lord Nobunaga yelled "Those are Yoshimoto's senior retainers (hatamoto) attack them."
About two in the afternoon we fought our way from the west [side of the valley] to the east and Yoshimoto's headquarters camp. About three hundred cavalrymen formed a defensive perimeter around Yoshimoto and attempted to retreat. They were attacked three, four, and then five times and their numbers declined until finally, they numbered only fifty riders. Lord Nobunaga dismounted and made his way to the vanguard, competing with his younger men to be the first to engage the enemy. He struck at the enemy but was knocked down. Hot-blooded young men fought desperately breaking [even] their sword guards in the heat of battle. Although it was a confusing battle, friend and foe were easily distinguished. There were countless dead and wounded, including horse-guards (umamawari) and pages. Hattori Koheta struck at Yoshimoto, but Hattori fell because he had already received a slash to the knee. [Then] Mori Shinsuke attacked Yoshimoto and took his head. People are saying that when Takehirasama was [recently] forced to take his own life at Kiyosu Castle and Mori Shinsuke captured Takehira's younger brother and saved his life that the blessing of the gods that he gained at the time brought him good luck today and was able to take Yoshimoto's head.
Again, this is Neilson's Shincho-Ko ki translation of the Battle of Okehazama. A superb job in my opinion. Nothing is perfect, but hopefully this will give the reader a clearer picture.
Nobunaga no tame!