Depriciation reserve

Are you talking about Accumulated Depreciation on fixed assets? It is created separately to keep balance in fixed assets account intact so that we always know at what cost the assets were purchased (since while presenting in fiancials, the accountant has to state cost less accumulated depreciation). Thus, instead of crediting the asset with depreciation amount, we credit separate Accumulated Depreciation on various assets accounts so that after both the accounts are netted, we get the net block (WDV) of that asset.

You can verify balance in this account by getting information about date of purchase of the asset, rate of depreciation and calculating total depreciation charged till date on each asset, which should match with the balance in Accumulated depreciation A/c. Normally, each year, accounts are audited and if they were audited last year by your firm only, you can simply match the opening balance with last year's audited cloaing balance.

Hope this solves your query.