Ask any Japanese man what he did in the summer holidays as a boy and he will tell you about beetles.

Kabutomushi, the Japanese rhinoceros beetle, has a single horn and can be eight centimetres long. Kuwagata, the stag beetles, have jaws. They are heavy, slow, spectacular insects, and every summer children here go out at night to find them.

They are not kept in a box for you. They are wild, in the oak woods of Gunma, and this tour teaches you to find them the way local children learn it.

It starts in daylight, which is the part nobody expects. You look for the trees. Kunugi and konara oaks that have been damaged and are leaking sap - the sap ferments and smells sweet and sour, and that smell is what the beetles come to. Once you can recognise a sap-running tree, you can find beetles anywhere in Japan for the rest of your life. That is the skill we are actually teaching.

We mark the trees, eat an early dinner, and go back after dark with torches. Beetles come to sap between about eight in the evening and two in the morning, and the first hours are enough.

You will also meet everything else that comes to fermenting sap: hornets, which we avoid and explain properly, moths, and the occasional flying squirrel overhead.

Everything is caught by hand, held, photographed, and put back on the tree before we leave. We do not take beetles home - they are part of the wood, and a caught beetle dies in a plastic box.

This is the best family night tour we run. Children go home having caught something real.

Your private van, driver-guide and the whole evening are yours alone. No other customers join.

Wild insects are not guaranteed. On a cold or wet night they do not come. We will tell you the forecast honestly, and if it is hopeless you can move your date to another day.