A landowner in Raghopur diara of Vaishali district may have stumbled upon Bihar's link to the Indus Valley civilisation.

Digging for piling work to build a house at the diara, around 10km north of Patna, the landowner, whose name is not being disclosed, came across thousands of large bricks. He used some and kept the rest as samples out of curiosity.

Around six months ago, the director of the state archaeological directorate, Atul Verma, visited the place and checked the samples. He carried two bricks back with him to Patna.

"Chief minister Nitish Kumar had asked us to visit the diara area as it is close to places of archaeological importance," Verma said. "The place is situated between Chechar in the north and Didarganj in the south, places of archaeological importance."

Chechar in Vaishali is a Neolithic site, while remains from the Mauryan period have been found during excavations at Didarganj in Patna.

Verma got the bricks tested and found that they bore similarities in thickness, width and length with those found from the Harappan sites. Bricks of both kinds have thickness, width and length in the ratio 1:2:4.

While one brick is 7.5cm thick, 15cm wide and 30cm long, another brick is 8cm thick, 16cm wide and 32cm long.

Also, the bricks at Raghopur were fire-burnt while those at the Harappan sites were sun-dried or fire-burnt.

Finding these similarities, Verma showed the bricks to experts who confirmed similarity in terms of proportion of thickness, width and length.

"During one of his visits to Patna, I showed the bricks to K.N. Dikshit, retired joint director-general of Archaeological Survey of India, considered an expert on Harappan sites," Verma said. "He confirmed similarities in dimensions."

Verma said the state archaeological directorate would now draft a team to undertake exploration work near the places from where the bricks were found.

"Our goal is to find more proof, like remains of pottery etc, to establish there was a settlement there in ancient times," Verma said.

"If similarities are found, we will publish our paper so that further research about the site can be carried out."

About deciphering the approximate year or age in which the bricks were manufactured, the director said the same would be calculated if remains of pottery and artefacts are found in the area. "We use potassium-argon dating method to ascertain the dates of artefacts or pottery," Verma said.

Vijay Kumar Choudhary, archaeologist and executive director of Bihar Heritage Development Society, confirmed Harappan bricks were in the proportion of 1:2:4 in terms of thickness, width and length. He said the state archaeological directorate's move was a step in the right direction to establish that human settlements existed in the area.

The place nearest to Bihar from where remains of Harappan settlement have been found is Alamgirpur near Meerut in Uttar Pradesh, around 950km northwest of Patna.