Brush contacts are for handing over material, instructions, money and so on. The officer and the agent carry out only one contact, in very populous places, in the underground, on full buses, at peak hours and when the crowds come out of stadiums, for example. Brush contact must be carried out with great precision otherwise the crowd may separate those taking part. On the other hand the transmission of the material must not attract attention especially if one of the participants is under strict surveillance. The check meeting is carried out in the same conditions as the routine meeting. However, the most junior of those taking part must not suspect that it is not a routine meeting and that he is in fact being checked. A number of GRU officers take up position before the meeting, in places where they can easily observe what is going on (for example, on observation platforms for tourists where there are powerful binoculars and telescopes installed). The entry of the agent to the meeting place is checked from a great distance. They check his punctuality, his behaviour, they watch for anybody who follows him, they observe the presence of any suspicious movement in the area of the meeting place prior to the meeting. After the agent has realised that nobody is going to come and meet him, the GRU officers may observe what he does, where he goes after the aborted meeting and what action he takes.
The secret rendezvous (Yavka) is often confused with the secret house or Yavotchnaya Kvartira. At the present time the term 'secret house' is not used in the GRU. It has been replaced by the term 'secret flat' or KK but the word Yavka is used to mean a meeting between two men who are unknown to each other, for example two illegals, or an agent with his new case officer. The secret rendezvous as an element of agent communications is given to all agents without exception - they are given the place, time, recognition signals, password and answer - because the secret rendezvous is essential for re-establishing lost contacts. For example, if in extreme circumstances the whole of the Soviet embassy was declared persona non grata and had to leave the country, the agent who had lost contact with his case officer would be obliged to go to a certain place on the 31st of every month which has thirty-one days, that is seven times a year, having previously agreed recognition signals (brief case in left hand, book in right hand, and so on). In the appointed place another person will come towards him and will give the previously arranged password to which the agent gives the proper reply. In giving the correct reply the agent shows to his new leader that he has not made a mistake and secondly that the agent acknowledges the authority of his new case officer. If nobody comes to the pre-arranged place, the agent is obliged to repeat the process until such time as somebody does appear to re-establish contact.
As the agent becomes more and more involved in his work, elements of non-personal contact gradually take the place of personal contact. The most experienced agents have only one element of personal contact - the secret rendezvous or Yavka -and several elements of non-personal contact. Let us examine these. First there is the long-range two-way radio link, generally imagined as a special portable radio set which may transmit information directly to the receiving centre on Soviet territory or to a Soviet ship or satellite. This classical element in all spy films is in practice only used in wartime. Instead agents and illegals are issued with small written instructions containing several types of ordinary current components which may be bought in any radio shop, and the means whereby they may be put together to make a long-range two-way set. This solves two problems at the same time. If an agent is arrested there is only to be found in his flat a pair of good Japanese receivers, a tape recorder and other components which can be bought in any shop. There is therefore no way that he can be suspected of any criminal activity. And secondly the problem of the transportation and secret storage of a radio set of comparatively large proportions is avoided. The GRU is continually looking at the market as regards radio sets and components, and working out new recommendations as to how they should be assembled. In times of war, however, quick-acting and ultra-quick-acting sets are used, exploiting technical means of radio transmission in seconds or micro-seconds. Satellites are used in conjunction with these sets and this makes it possible to transmit information on a narrow radio beam vertically overhead. The long-range one-way radio link does not replace, but augments the two-way link. The most convenient, reliable and secure type of link is inevitably the one by which the agent receives from the Centre. One-way radio links are usually broadcast by Soviet radio stations or special ships or polar stations to be received anywhere in the world by ordinary radio receivers. Instructions to the agent are transmitted in the form of previously agreed phrases or numbers in ordinary radio programmes, or as a simple numerical code. Even if a police force should by some means or another guess that the transmission they are hearing is not a coded transmission for cosmonauts or warships, they cannot possibly determine for which spy it is destined, or even which country. The agent who hears such a transmission is also not exposed to any great risk. However, for the GRU it is often necessary that the agent himself transmits. For this the short-range radio link exists. The agent transmits information to the Soviet embassy with the help of small transmitters, like the sort of walkie-talkie sets which can be bought in any shop and which are used for guiding model aeroplanes and ships (one cannot help noticing how many aerials there are on the roof of the Soviet embassy). In this type of radio exchange the GRU takes the cover of a fireman, ambulance driver, construction worker or a policeman. All radio conversations within the city limits are thoroughly studied by GRU specialists and any of them may be used by the GRU for its dark ends. A short-range special link is an alternative to short-range radio links. In connection with increasing the monitoring of radio exchanges, the GRU frequently undertakes the transmission of signals under water. One fisherman will transmit signals by means of a rod put in the water and another several kilometres distant from him will receive the signal by using the same method. Or water and gas pipes can be used. Significant research is also going on in the field of electro-optical communications.
Dead-letter boxes are the favourite GRU means of contact. They have the most universal application and in addition to communications they may be used for the storage of everything that has to do with a spy's work - documents, money, radio sets, special photographic equipment, for example. Thousands of types of dead-letter boxes are known, from cracks in gravestones and brickwork to specially devised magnetic 'letter boxes' in the form of metal nuts. Applied to the structure of a bridge among thousands of similar nuts and rivets this device is easily hidden and just as easy to undo. The GRU also makes wide use of boxes constructed in the form of a plastic hollow wedge with a lid. These can very easily be pushed into the ground in any public park. Underwater dead-letter boxes are also widely used.
Their selection is always a complicated and responsible business. The primary criterion is that as far as possible they must not be prone to accidental discovery. They are threatened by many possible happenings: they may be found by children, by the police, even by archaeologists. There may be floods, or the heat of summer may affect them. Someone may start building on the site. All this must be taken into account. Equally important is that the dead-letter box's location must be easy to describe to another person, even by somebody who only knows about it at secondhand. It must also be located in a place where it is possible for the case officer to go at any time with a plausible cover story for his presence there. Some random examples from GRU practice are worth describing.
As a general principle of security, each dead-letter box (DLB) may only be used once. Documents on all DLBs are stored in the GRU command point and after the completion of a DLB operation the document is stamped 'used' and transferred to the archives. An officer at a command point, working in a GRU top secret archive, once discovered the description of a DLB on which there was no 'used' stamp. The document was very old, pre-war. The DLB has been selected in 1932 and three years later some material had been put in it - money and valuables for the use of the illegal residency in case of emergency, apparently 'in various currencies to a total sum of 50,000 American dollars'. The officer carefully inspected the document again, but there was nothing on it to show that the DLB had been emptied. The officer informed his chief of what he had found and he in his turn informed the GRU chief, who decided on an investigation. The affair was not complicated and a week later the investigation disclosed that the dead-letter box had belonged to the Hamburg illegal residency which in 1937 had been recalled to Moscow lock, stock and barrel for 'instructions', and shot. All the materials of the residency had been handed in to the archives, together with the document about the unused DLB. The new officers who took the place of those who had been shot were completely inexperienced and started work with new sets of documents. There was no time, in any case, to look into the old documents. Then the new GRU staff was also liquidated. So there were many documents which were completely forgotten and simply collected dust in the archives.
The GRU chief took two decisions, firstly, to nominate a group of specially trusted officers for permanent archive work- perhaps something else of interest might be discovered - and secondly, to give an order to one of the GRU residencies in West Germany to find this old unused DLB. Suppose it was still there. If it was, then the value of its contents would have increased many times.
In fact the DLB had survived, in spite of the war, the fierce bombing of Hamburg, the rebuilding of the city after the war, and the enormous expansion in the development of the city. The DLB consisted of a hermetically sealed container, about the size of a small suitcase, which had been buried at the bottom of a lake in a quiet park. For greater security it had been covered with an old tombstone which had been sprinkled all over with sand and silt. The container was removed to Moscow and opened there. Much to the disappointment of all those present, all that was inside was a few dozen old-fashioned silver watches of very little value, a hundred or so American dollars and a few thousand crisp German Marks of the time of the Third Reich.